Moderate-intensity Cycling Exercise Research Articles

Middle cerebral artery blood velocity and end-tidal carbon dioxide responses to moderate intensity cycling in children, adolescents, and adults.

This study investigated the middle cerebral artery blood velocity (MCAv) response to constant work-rate moderate-intensity cycling exercise in 21 children (9.3 ± 0.8 yr), 17 adolescents (12.3 ± 0.4 yr), and 20 young adults (23.6 ± 2.4 yr). Participants completed an incremental ramp test to exhaustion on a cycle ergometer to determine maximal oxygen uptake and gas exchange threshold (GET) before completing three 6-min transitions at a moderate intensity (90% GET) on separate visits. On each visit, bilateral MCAv was measured by transcranial Doppler ultrasonography and breath-by-breath end-tidal carbon dioxide ([Formula: see text]) via a metabolic cart. Data were ensemble-averaged for each participant and analyzed using a monoexponential model. Absolute MCAv was significantly higher throughout exercise in children and adolescents compared with adults (P < 0.001). Children had a significantly lower relative increase in MCAv from baseline (∼12%) compared with adolescents (∼20%) and adults (∼18%, P < 0.040). All adolescents and adults had a monoexponential rise in MCAv and [Formula: see text], but this was observed in only eight children. Children and adolescents had a significantly faster MCAv time constant (τ, 12 ± 6 and 14 ± 8 s, respectively) compared with adults (27 ± 9 s, P < 0.001). MCAv τ was positively associated with faster [Formula: see text] τ in adolescents (r = 0.70, P = 0.002) but not in children (r = -0.20, P = 0.640). Time- and amplitude-based response parameters of MCAv kinetics were significantly associated with [Formula: see text] kinetics in adults (r = 0.50-0.74, P ≤ 0.025), but not in children (r = -0.19 to -0.48, P > 0.227). These findings suggest that the transition from childhood to adulthood impacts the MCAv response to exercise and the relationships between [Formula: see text] and MCAv kinetics during exercise.NEW & NOTEWORTHY This is the first study to find that children have smaller increases in Δ%MCAv (∼12%) during moderate-intensity exercise compared with adolescents and adults (∼18%-20%). Furthermore, MCAv kinetics were significantly faster in children and adolescents, compared with adults. MCAv kinetic responses were significantly and positively associated with [Formula: see text] kinetics in adults, but not in children. These novel data also suggest that the regulatory role of [Formula: see text] on MCAv during exercise begins to strengthen during adolescence.

Impact of the Menstrual Cycle on the Cardiovascular and Ventilatory Responses During Exercise in Normoxia and Hypoxia.

Citherlet, Tom, Antoine Raberin, Giorgio Manferdelli, Nicolas Bourdillon, and Grégoire P Millet. Impact of the menstrual cycle (MC) on the cardiovascular and ventilatory responses during exercise in normoxia and hypoxia. High Alt Med Biol. 00:00-00, 2024. Introduction: Ovarian hormones influence several physiological functions in women. This study investigated how the hormonal variations across the menstrual cycle (MC) impact cardiovascular and ventilatory responses during rest and moderate exercise in normobaric hypoxia. Methods: Thirteen eumenorrheic women were tested during the early follicular (Fol1), late follicular (Fol2), and mid-luteal (Lut3) phases with measurement of hormonal levels. Heart rate (HR) variability, blood pressure, and baroreflex sensitivity (BRS) were evaluated at rest in normoxia. Ventilation (VE), peripheral oxygen saturation, and HR were monitored at rest and during moderate-intensity cycling exercise in hypoxia (FiO2 = 14%). Results: Despite expected hormone level variations, no significant changes were observed across the MC in HR variability (root mean square of successive differences; 64 (95% confidence interval [47, 81]) at Fol1, 54 [42, 66] at Fol2, 60 [44, 77] ms at Lut3), blood pressure (mean blood pressure; 85 [79, 90]), 87 [81, 93]), 84 [77, 92] mmHg), BRS (26 [17, 36], 28 [20, 35], 23 [17, 29] ms/mmHg), VE (rest: 8.9 [7.9, 9.8], 9.5 [9.0, 9.9], 9.0 [8.1, 9.9]; exercise: 53 [41, 66], 51.1 [36.4, 65.7], 54.4 [34.0, 74.8] l/min), peripheral oxygen saturation (rest: 89.8 [87.4, 92.1], 91.9 [88.7, 95.0], 90.2 [87.8, 92.6]; exercise: 80.5 [77.4, 83.5], 84.4 [80.4, 88.3], 81.9 [78.3, 85.4] %) HR (rest: 69.7 [60.2, 79.1], 70.8 [63.2, 78.3], 70.5 [64.0, 77.0]; exercise: 148 [136, 160], 146 [132, 161], 146 [132, 160] bpm), and cycling efficiency (0.17 [0.16, 0.18], 0.17 [0.13, 0.21], 0.16 [0.15, 0.18] %) (all p > 0.05). Discussion: From a practical point of view, there is no strong evidence of any usefulness of monitoring hormonal variations and the MC phases for women exercising in hypoxia.

The effects of acute aerobic exercise on appetite-regulating parameters and energy intake in males with obesity.

To investigate the effects of moderate-intensity aerobic exercise on appetite control parameters, appetite perceptions, and energy intake in sedentary males with obesity. Eleven males with obesity (body fat percentage 36.5 ± 2.5%, body mass index 35.3 ± 4.2 kg/m2, V̇O2peak 29 ± 3.1 mL·kg-1·min-1) completed two experimental sessions: (1) no exercise (CTRL) and (2) 60 min of moderate-intensity cycling exercise at 60% V̇O2peak (MICT) in a crossover design. Blood analysis included growth differentiation factor 15 (GDF-15), total ghrelin, peptide tyrosine tyrosine3-36 (PYY3-36), total glucagon-like peptide-1 (GLP-1), insulin, and glucose, as well as subjective appetite perceptions were measured in specific intervals. A standard breakfast at 0 h and an ad libitum meal postexercise was provided. GDF-15 (95% confidence interval [CI]: [2.48-27.28] ng/L, p = 0.021) increased immediately following MICT compared to CTRL. However, there were no differences for PYY3-36 (p = 0.480, ), total ghrelin (p = 0.646, ), and total GLP-1 (p = 0.451, ) between sessions. Appetite perceptions (95% CI: [(-20.38)-(-6.16)] mm, p = 0.001) were suppressed following MICT though energy intake was not different between the sessions (95% CI: [(-1904.9)-928.1] kJ, p = 0.480). Sixty minutes of MICT increased GDF-15 while suppressing appetite perceptions in individuals with obesity. There was no energy compensation postexercise.

Prefrontal Cortex Oxygenation During Exercise in Older Adults with Motoric Cognitive Risk Syndrome.

Motoric cognitive risk syndrome (MCR) is a pre-dementia syndrome characterized by subjective memory complaints and gait impairments that may be related to lower prefrontal cortex (PFC) function. Acute bouts of aerobic exercise are shown to improve PFC function, however, the acute effects of exercise on PFC oxygenation have not yet been examined in MCR. This study aims to characterize the PFC oxygenation responses during acute exercise in older adults with MCR. Nineteen older adults with MCR performed a submaximal cycling exercise protocol. Functional near-infrared spectroscopy (fNIRS) is used to measure concentrations of oxygenated (OxyHb) and deoxygenated (DeoxyHb) hemoglobin from the PFC. There is a trend for increased OxyHb concentrations and decreased DeooxyHb concentrations during exercise. Exercise also induced significant increases in ratings of perceived exertion (RPEs) and heart rate. A significant, positive correlation between PFC OxyHb and RPEs during the cycling exercise are also observed. The findings reveal that PFC oxygenation increases during exercise in an intensity-dependent manner and the subjective perception of exertion is associated with the magnitude of PFC oxygenation. These results suggest that moderate-intensity cycling exercise may have beneficial effects on increasing cerebral blood flow in the PFC of older adults with MCR.

Caffeine Attenuates Exacerbated Central Fatigue during Moderate-Intensity Cycling Exercise in Women with Fibromyalgia.

To compare the development of fatigability during a moderate-intensity cycling exercise between women with fibromyalgia (FM) and control women (CON) after acute ingestion of caffeine and placebo. Ten FM and 10 CON women performed a 30-min moderate-intensity cycling exercise 1 h after the ingestion of a capsule containing either caffeine or a placebo. Fatigability and its central and peripheral determinants were determined via changes from pre- to post-15 and post-30 min of exercise in maximal voluntary isometric contractions, voluntary activation (VA), and quadriceps potentiated twitch torque ( Qtw-pot ), respectively. Heart rate, muscle oxygen saturation, perceptive responses, mood state, localized and widespread pain, and sleepiness were also monitored during and after exercise. There was a time versus group interaction for maximal voluntary isometric contraction and VA ( P < 0.001) but not for Qtw-pot ( P = 0.363), indicating a greater rate of fatigability development, mainly caused by central mechanisms, in the FM than in the CON group. There was also a main effect of condition for VA ( P = 0.011), indicating that caffeine attenuates central mechanisms of fatigability in both groups. Caffeine ingestion also increased muscle oxygenation, perceived vigor, and energy, and decreased leg muscle pain, sleepiness, and perceived fatigue in both groups. However, caffeine improved perceived pleasure/displeasure and exercise adherence likelihood only in the FM group. Compared with CON, women with FM present a greater rate of fatigability during exercise, mainly of central origin. Caffeine seems to be a promising bioactive to counteract the central mechanisms of fatigability and improve the exercise experience among FM women.

Exercise transiently increases the density of incipient blood clots in antiplatelet-treated lacunar stroke patients

IntroductionOlder individuals and, in particular, individuals at risk of recurrent stroke, may be susceptible to thrombosis when participating in exercise, however, this aspect has not been well investigated.MethodsClot microstructure and conventional markers of thrombotic risk were determined in twenty lacunar stroke patients and fifteen healthy age-matched controls before, immediately after and 1 h after a bout of moderate intensity cycling exercise. Data were analyzed using a linear mixed model approach.ResultsAt rest, clot microstructure (1.69 ± 0.07 vs. 1.64 ± 0.05, corresponding to a difference of ~ 50% in normalized clot mass; p = 0.009) and thrombocyte count (73%; p < 0.0001) were higher, and activated partial thromboplastin time was lower (18%; p = 0.0001) in stroke patients compared to age-matched controls. Acute exercise increased thrombogenic markers similarly in the two groups: incipient clot microstructure (1.69 ± 0.07 vs. 1.74 ± 0.05; p = 0.0004 and 1.64 ± 0.05 vs. 1.71 ± 0.04; p < 0.0001, for stroke and controls respectively), plasma fibrinogen (12%; p < 0.0001 and 18%; p < 0.0001, for stroke and controls respectively) and the combined coagulation factors II, VII and X (p = 0.0001 and p < 0.0001, for stroke and controls respectively).ConclusionThe results show that exercise transiently increases the risk of blood clot formation in both stroke patients and controls, however, due to the higher baseline thrombogenicity in stroke patients, the post exercise risk of forming blood clots may be higher in this group.Trial registrationRegistered at ClinicalTrials.gov (NCT03635177).

P096 The Effect of Moderate-Intensity Exercise on Sleep Quality and Quantity in Healthy Adult Males

Abstract Introduction Acute exercise may have the ability to disrupt sleep in healthy adults. Given the popularity of afternoon exercise, it is important to determine how this affects sleep. Therefore, the aim of this study was to investigate the effect of afternoon moderate-intensity cycling exercise on objective and subjective sleep in healthy adult males. Methods To assess the effect of moderate-intensity afternoon exercise on sleep quality and quantity, 12 healthy adult males who were identified as good sleepers completed a repeated-measures, counter-balanced, crossover study design with two conditions (moderate-intensity aerobic exercise or no exercise). The exercise task involved cycling for 40 minutes at 70%HRmax and was completed ~15:30h. Polysomnography was used to measure sleep during a 9-h sleep opportunity (23:00h to 08:00h). Results There were no statistically significant differences in objective or subjective sleep between conditions. Exercise had a medium-sized effect on reducing total sleep time (mean ± SD; control 493.71 ± 12.59 mins vs exercise: 471.46 ± 55.19 mins; Cohen’s d: 0.56), sleep efficiency (mean ± SD; control 91.43 ± 2.33 % vs exercise: 87.31 ± 10.22 %; Cohen’s d: 0.56), and increasing REM onset latency (mean ± SD; control: 76.13 ± 45.10 mins vs exercise: 102.75 ± 46.85 mins; r: -0.33) (all p &amp;gt; 0.05). Discussion Healthy adult males can complete afternoon moderate-intensity exercise without compromising subsequent sleep. Individual responses in objective sleep outcomes may vary after exercise.

Acute exercise and high-glucose ingestion elicit dynamic and individualized responses in systemic markers of redox homeostasis.

Biomarkers of oxidation-reduction (redox) homeostasis are commonly measured in human blood to assess whether certain stimuli (e.g., high-glucose ingestion or acute exercise) lead to a state of oxidative distress (detrimental to health) or oxidative eustress (beneficial to health). Emerging research indicates that redox responses are likely to be highly individualized, yet few studies report individual responses. Furthermore, the effects of complex redox stimuli (e.g., high-glucose-ingestion after exercise) on redox homeostasis remains unclear. We investigated the effect of acute exercise (oxidative eustress), high-glucose ingestion (oxidative distress), and high-glucose ingestion after exercise (both oxidative eu/distress), on commonly measured redox biomarkers in serum/plasma. In a randomized crossover fashion, eight healthy men (age: 28 ± 4 years; BMI: 24.5 ± 1.5 kg/m2 [mean ± SD]) completed two separate testing conditions; 1) consumption of a high-glucose mixed-nutrient meal (45% carbohydrate [1.1 g glucose.kg-1], 20% protein, and 35% fat) at rest (control trial), and 2) consumption of the same meal 3 h and 24 h after 1 h of moderate-intensity cycling exercise (exercise trial). Plasma and serum were analyzed for an array of commonly studied redox biomarkers. Oxidative stress and antioxidant defense markers (hydrogen peroxide, 8-isoprostanes, catalase, superoxide dismutase, and nitrate levels) increased immediately after exercise (p < 0.05), whereas nitric oxide activity and thiobarbituric acid reactive substances (TBARS) remained similar to baseline (p > 0.118). Nitric oxide activity and nitrate levels decreased at 3 h post-exercise compared to pre-exercise baseline levels. Depending on when the high-glucose mixed nutrient meal was ingested and the postprandial timepoint investigated, oxidative stress and antioxidant defense biomarkers either increased (hydrogen peroxide, TBARS, and superoxide dismutase), decreased (hydrogen peroxide, 8-isoprostanes, superoxide dismutase, nitric oxide activity, nitrate, and nitrite), or remained similar to pre-meal baseline levels (hydrogen peroxide, 8-isoprostanes, TBARS, catalase, superoxide dismutase and nitrite). Redox responses exhibited large inter-individual variability in the magnitude and/or direction of responses. Findings highlight the necessity to interpret redox biomarkers in the context of the individual, biomarker measured, and stimuli observed. Individual redox responsiveness may be of physiological relevance and should be explored as a potential means to inform personalized redox intervention.

Differences in the prefrontal cortex responses of healthy young men performing either water-based or land-based exercise at light to moderate intensity

Cerebral blood flow increases more during water-based exercise than land-based exercise owing to the effects of end-tidal CO2 (PETCO2) and mean arterial pressure (MAP) changes due to water immersion. However, it is unclear whether oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex (PFC) are increased more by water-based or land-based exercise. We hypothesized that oxy-Hb concentrations in the PFC are higher during water-based exercise than land-based exercise when the exercise intensity is matched. To test this hypothesis, 10 healthy participants (age: 24.2 ± 1.7 years; height: 1.75 ± 0.04 m; weight: 69.5 ± 5.2 kg) performed light- to moderate-intensity cycling exercise in water (water-based cycling (WC); chest-high water at 30 °C) and on land (LC). Stroke volume, cardio output, heart rate, MAP, respiratory rate, PETCO2, and oxy-Hb in the PFC were assessed during 15 min of exercise, with exercise intensity increased every 5 min. Both WC and LC significantly increased oxy-Hb concentrations in the PFC as exercise intensity was increased (intensity effect: p < 0.001). There was no significant difference in oxy-Hb concentrations during WC and LC in most prefrontal areas, although significant differences were found in areas corresponding to the left dorsolateral PFC (exercise effect: p < 0.001). Thus, WC and LC increase oxy-Hb concentrations in the PFC in a similar manner with increasing exercise intensity, but part of the PFC exhibits enhanced oxy-Hb levels during WC. The neural response of the PFC may differ during water-based and land-based exercise owing to differences in external information associated with water immersion.

Blood flow restriction accelerates aerobic training-induced adaptation of {dot{text{V}}}{text{O}}_{2} kinetics at the onset of moderate-intensity exercise

It is unclear whether blood flow restriction (BFR) accelerates the adaptation of the time constant (τ) of phase II oxygen uptake ( {dot{text{V}}}{text{O}}_{2} ) kinetics in the moderate-intensity exercise domain via moderate-intensity aerobic training. Therefore, healthy participants underwent moderate-intensity [45–60% {dot{text{V}}}{text{O}}_{2} Reserve] aerobic cycle training with or without BFR (BFR group, n = 9; CON group, n = 9) for 8 weeks to evaluate {dot{text{V}}}{text{O}}_{2} kinetics during moderate-intensity cycle exercise before (Pre) and after 4 (Mid) and 8 (Post) weeks of training. Both groups trained for 30 min, 3 days weekly. BFR was performed for 5 min every 10 min by applying cuffs to the upper thighs. The τ significantly decreased by Mid in the BFR group (23.7 ± 2.9 s [Pre], 15.3 ± 1.8 s [Mid], 15.5 ± 1.4 s [Post], P < 0.01) and by Post in the CON group (27.5 ± 2.0 s [Pre], 22.1 ± 0.7 s [Mid], 18.5 ± 1.9 s [Post], P < 0.01). Notably, the BFR group’s τ was significantly lower than that of the CON group at Mid (P < 0.01) but not at Post. In conclusion, BFR accelerates the adaptation of the {dot{text{V}}}{text{O}}_{2} kinetics of phase II by moderate-intensity aerobic training.

Effect of recovery time on dot{V}{text{O}}_{2}-ON kinetics in humans at the onset of moderate-intensity cycling exercise

Purposeτ of the primary phase of dot{V}{text{O}}_{{2{text{A}}}} kinetics during square-wave, moderate-intensity exercise mirrors that of PCr splitting (τPCr). Pre-exercise [PCr] and the absolute variations of PCr (∆[PCr]) occurring during transient have been suggested to control τPCr and, in turn, to modulate dot{V}{text{O}}_{{2{text{A}}}} kinetics. In addition, dot{V}{text{O}}_{{2{text{A}}}} kinetics may be slower when exercise initiates from a raised metabolic level, i.e., from a less-favorable energetic state. We verified the hypothesis that: (i) pre-exercise [PCr], (ii) pre-exercise metabolic rate, or (iii) ∆[PCr] may affect the kinetics of muscular oxidative metabolism and, therefore, τ.MethodsTo this aim, seven active males (23.0 yy ± 2.3; 1.76 m ± 0.06, dot{V}{text{O}}_{2max }: 3.32 L min−1 ± 0.67) performed three repetitions of series consisting of six 6-min step exercise transitions of identical workload interspersed with different times of recovery: 30, 60, 90, 120, 300 s.ResultsMono-exponential fitting was applied to breath-by-breath dot{V}{text{O}}_{{2{text{A}}}}, so that τ was determined. τ decays as a first-order exponential function of the time of recovery (τ = 109.5 × e(−t/14.0) + 18.9 r2 = 0.32) and linearly decreased as a function of the estimated pre-exercise [PCr] (τ = − 1.07 [PCr] + 44.9, r2 = 0.513, P < 0.01); it was unaffected by the estimated ∆[PCr].ConclusionsOur results in vivo do not confirm the positive linear relationship between τ and pre-exercise [PCr] and ∆[PCr]. Instead, dot{V}{text{O}}_{{2{text{A}}}} kinetics seems to be influenced by the pre-exercise metabolic rate and the altered intramuscular energetic state.

Perceived Exertion Is Elevated By A Dual-task Of Cognitive Performance And Aerobic Exercise

In many sports (e.g., football, lacrosse, rugby, etc.), the need to perform a dual-task (e.g., decision-making during exercise) is unavoidable. Purpose: Given that prolonged continuous performance of a cognitively demanding task increases mental fatigue, we hypothesized that a sustained cognitive effort superimposed during aerobic exercise would compound the increased rating of perceived exertion (RPE). Methods: Twenty-one healthy, young males (aged 22 ± 2 yrs; VO2 peak = 46 ± 5 ml/kg/min) performed two trials [i.e., exercise-cognition (EX-Cog) and exercise-only (EX)] in a randomised-crossover design. In EX-Cog trial, participants performed 50-min moderate-intensity (60% peak oxygen uptake) cycling exercise and sustained 50-min Stroop task, simultaneously. In EX trial, participants performed 50-min moderate-intensity cycling exercise. RPE was assessed via the Borg scale during the final 10 seconds of exercise in both conditions. Mental fatigue (visual analog scale) and heart rate (HR; HR monitor) in response to exercise were also recorded. RPE was analyzed using Wilcoxon signed-rank test. Changes in mental fatigue and HR in response to exercise were analyzed using a two-way (trial × time) repeated-measures analysis of variance. Results: The elevations in mental fatigue and HR were identical during both trials (both P < 0.05). In contrast, RPE was higher during EX-Cog (EX-Cog median 15; IQR 15.0 to 17.0 vs. EX median 15; IQR 14.0 to 16.5, P = 0.012). Conclusions: These findings indicate that dual-tasking increases perceived exertion yet fails to incur additional mental fatigue or cardiovascular demand which may have implications for decision-making during sport.

Test-retest reliability of lung diffusing capacity for nitric oxide during light to moderate intensity cycling exercise

This study examined test-retest reliability of single-breath lung diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO) during exercise. Sixteen healthy subjects (age 20–67 years) performed DLNO-DLCO tests during light and moderate intensity cycling exercise at 50% and 80% of individual anaerobic threshold (IAT). Primary endpoint was DLNO at 80% IAT. Precision of DLNO, DLCO, and alveolar volume was quantified by within-subject standard deviation (SDws, measurement error) and intraclass correlation coefficients (ICC). Reproducibility was determined by SDws* 2.77. Overall, reliability was excellent for all outcomes. SDws and reproducibility for DLNO at 80% IAT were 4.6 and 12.7 mL.min−1.mmHg−1, and the ICC was 0.99 (95% confidence interval 0.98–0.99). Median breathlessness at 80% IAT was 4 (interquartile range 3–6) on a 0–10 scale. Our data suggest excellent reliability of single-breath DLNO during moderate intensity exercise, but perceived levels of breathlessness may limit its usefulness, especially at exercise intensities beyond IAT.

Effects of dietary nitrate on the O2 cost of submaximal exercise: Accounting for “noise” in pulmonary gas exchange measurements

ABSTRACT Dietary nitrate (NO3 –) supplementation can reduce the oxygen cost of submaximal exercise, but this has not been reported consistently. We hypothesised that the number of step transitions to moderate-intensity exercise, and corresponding effects on the signal-to-noise ratio for pulmonary O2, may be important in this regard. Twelve recreationally active participants were assigned in a randomised, double-blind, crossover design to supplement for 4 days in three conditions: 1) control (CON; water); 2); PL (NO3 –-depleted beetroot juice); and 3) BR (NO3 –-rich beetroot juice). On days 3 and 4, participants completed two 6-min step transitions to moderate-intensity cycle exercise. Breath-by-breath O2 data were collected and O2 kinetic responses were determined for a single transition and when the responses to 2, 3 and 4 transitions were ensemble-averaged. Steady-state O2 was not different between PL and BR when the O2 response to one-, two- or three-step transition was compared but was significantly lower in BR compared to PL when four-step transitions was considered (PL: 1.33 ± 0.34 vs. BR: 1.31 ± 0.34 L·min−1, P < 0.05). There were no differences in pulmonary O2 responses between CON and PL (P > 0.05). Multiple step transitions may be required to detect the influence of NO3 − supplementation on steady-state O2.

Magnitude, timing and duration of mood state and cognitive effects of acute moderate exercise in major depressive disorder

BackgroundAcute exercise generally improves mood state and cognitive functioning in healthy adults. However, the impact of acute exercise on primary symptoms in adults with major depressive disorder (MDD) is poorly understood. The present randomized cross-over study evaluated the magnitude, timing, and duration of the psychological effects of 30 min of moderate-intensity cycling exercise compared to quiet rest in 30 adults (21 female) with MDD. MethodsDepressed mood state (Profile of Mood States Short Form-Depression; POMS-D), state anhedonia (anhedonia Visual Analog Scale [VAS], and Dimensional Anhedonia Rating Scale [DARS]), and cognition (inhibition via Stroop and working memory via the 2-back task) were assessed pre, mid, post, 25-, 50- and 75-min after each session. ResultsGeneralized estimating equations demonstrated significant session by time interactions for POMS-D and VAS indicating small-to-large improvements in mood state and anhedonia up to 75 min post-exercise (p < 0.05; Cohen’s d ranges: POMS [-0.69, -0.95]; DARS, [-0.02, 0.16]; VAS [0.33, 0.83]) with greater immediate effects that lessened somewhat across time. For cognition, Stroop reaction time improved during exercise, but was worse at 25- and 50-min post-exercise compared to quiet rest (p < 0.05); no differences were found for 2-back reaction time. LimitationsThe small sample and continued psychological effects at 75 min indicate a potentially longer-lasting response than was measured herein. ConclusionPerforming short bouts of moderate intensity exercise appears to be effective for management of key symptoms (anhedonia, depressed mood state) in adults with MDD. The time immediately post-exercise may be ideal for performing emotionally challenging tasks and/or tasks where a low symptom severity would be helpful (e.g., psychotherapy).

The effects of exercise intensity and duration on the relationship between the slow component of V̇O2 and peripheral fatigue.

If the development of the oxygen uptake slow component (V̇O2SC ) and muscle fatigue are related, these variables should remain coupled in a time- and intensity-dependent manner. 16 participants (7 females) visited the laboratory on 7 separate occasions: (1) three 6-minutes moderate-intensity cycling exercise bouts proceeded by a ramp incremental test; (2-3) 30-minutes constant power output (PO) exercise bout to determine the maximal lactate steady state (MLSS); (4-7) constant-PO exercise bouts to task failure (TTF), pseudorandomized order, at (i) 15% below the PO at MLSS; (ii) 10W below MLSS; (iii) MLSS; (iv) 10W above MLSS (first intensity and randomized order thereafter). Neuromuscular fatigue was characterized by isometric maximal voluntary contractions and femoral nerve electrical stimulation of knee extensors to measure peripheral fatigue at baseline, at min 5, 10, 20, 30 and TTF. Pulmonary oxygen uptake (V̇O2 ) was continuously recorded during the constant-PO bouts and V̇O2SC was characterized based on each individual V̇O2 kinetics during moderate transitions. The development of V̇O2SC and peripheral fatigue were correlated across time (r2 adj range of 0.64-0.80) and amongst each exercise intensity (r2 adj range of 0.26-0.30) (all P<.001). Also, TTF was correlated with V̇O2SC and neuromuscular fatigue parameters (r2 adj range of 0.52-0.82, all P<.001). The V̇O2SC and peripheral fatigue development are correlated throughout the exercise in a time- and intensity-dependent manner, suggesting that the V̇O2SC may depend on muscle fatigue even if the mechanisms of reduced contractile function are different amongst intensities.

Exercise in Water Provides Better Cardiac Energy Efficiency Than on Land.

Although water-based exercise is one of the most recommended forms of physical activity, little information is available regarding its influence on cardiac workload and myocardial oxygen supply-to-demand. To address this question, we compared subendocardial viability ratio (SEVR, the ratio of myocardial oxygen supply-to-demand), cardiac inotropy (via the maximum rate of aortic pressure rise [dP/dTmax]), and stroke volume (SV, via a Modelflow method) responses between water- and land-based exercise. Eleven healthy men aged 24 ± 1 years underwent mild- to moderate-intensity cycling exercise in water (WC) and on land (LC) consecutively on separate days. In WC, cardiorespiratory variables were monitored during leg cycling exercise (30, 45, and 60 rpm of cadence for 5 min each) using an immersible stationary bicycle. In LC, each participant performed a cycling exercise at the oxygen consumption (VO2) matched to the WC. SEVR and dP/dTmax were obtained by using the pulse wave analysis from peripheral arterial pressure waveforms. With increasing exercise intensity, SEVR exhibited similar progressive reductions in WC (from 211 ± 44 to 75 ± 11%) and LC (from 215 ± 34 to 78 ± 9%) (intensity effect: P < 0.001) without their conditional differences. WC showed higher SV at rest and a smaller increase in SV than LC (environment-intensity interaction: P = 0.009). The main effect of environment on SV was significant (P = 0.002), but that of dP/dTmax was not (P = 0.155). SV was correlated with dP/dTmax (r = 0.717, P < 0.001). When analysis of covariance (ANCOVA) was performed with dP/dTmax as a covariate, the environment effect on SV was still significant (P < 0.001), although environment-intensity interaction was abolished (P = 0.543). These results suggest that water-based exercise does not elicit unfavorable myocardial oxygen supply-to-demand balance at mild-to-moderate intensity compared with land-based exercise. Rather, water-based exercise may achieve higher SV and better myocardial energy efficiency than land-based exercise, even at the same inotropic force.

Acute Exercise Modulates the Excitability of Specific Interneurons in Human Motor Cortex

Acute exercise can modulate the excitability of the non-exercised upper-limb representation in the primary motor cortex (M1). Accumulating evidence demonstrates acute exercise affects measures of M1 intracortical excitability, with some studies also showing altered corticospinal excitability. However, the influence of distinct M1 interneuron populations on the modulation of intracortical and corticospinal excitability following acute exercise is currently unknown. We assessed the impact of an acute bout of leg cycling exercise on unique M1 interneuron excitability of a non-exercised intrinsic hand muscle using transcranial magnetic stimulation (TMS) in young adults. Specifically, posterior-to-anterior (PA) and anterior-to-posterior (AP) TMS current directions were used to measure the excitability of distinct populations of interneurons before and after an acute bout of exercise or rest. Motor evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) were measured in the PA and AP current directions in M1 at two time points separated by 25 min of rest, as well as immediately and 30 min after a 25-minute bout of moderate-intensity cycling exercise. Thirty minutes after exercise, MEP amplitudes were significantly larger than other timepoints when measured with AP current, whereas MEP amplitudes derived from PA current did not show this effect. Similarly, SICI was significantly decreased immediately following acute exercise measured with AP but not PA current. Our findings suggest that the excitability of unique M1 interneurons are differentially modulated by acute exercise. These results indicate that M1 interneurons preferentially activated by AP current may play an important role in the exercise-induced modulation of intracortical and corticospinal excitability.

Acute Caffeine Intake Reduces Perceived Exertion But Not Muscle Pain during Moderate Intensity Cycling Exercise in Women with Fibromyalgia

Objective Exacerbated perceived exertion and muscle pain responses during exercise might limit physical activity practice in fibromyalgia patients. Thus, nutritional strategies that can reduce perceived exertion and muscle pain during exercise in fibromyalgia patients would be useful. The purpose of this study was to investigate the effects of acute caffeine intake on the perceptions of exertion and muscle pain during a moderate intensity exercise in women with fibromyalgia.Method: Using a randomized, double-blinded, placebo-controlled and crossover experimental design, eleven sedentary women diagnosed with fibromyalgia (age: 44.6 ± 10.5 years; body mass index: 28.5 ± 4.5 kg.m−2) ingested a capsule containing either caffeine (5 mg per kg of body mass) or cellulose (placebo), 60 minutes before performing a 30-minute constant-load cycling exercise, with work rate fixed at 50% of their individual peak workload attained in an incremental exercise test. Ratings of perceived leg muscle pain and perceived exertion were assessed every 5 minutes of exercise.Results: The perceived leg muscle pain was similar (F(1,10) = 1.18, p = 0.30, ŋ2 = 0.11) between caffeine (2.1 ± 1.2 arbitrary units) and placebo conditions (2.2 ± 0.9 arbitrary units). The perceived exertion, however, was on average 8 ± 6% lower (F(1,10) = 12.13; p = 0.006; ŋ2 = 0.55) during exercise in the caffeine condition (12.4 ± 1.3 arbitrary units) than in the placebo condition (13.1 ± 1.1 arbitrary units).Conclusions: These findings indicate that acute caffeine intake could be an attractive strategy to attenuate the exacerbated perceived exertion of fibromyalgia patients during moderate intensity exercise.

Exercise acutely increases vitaminD receptor expression in Tlymphocytes in vitaminD-deficient men, independent of age.

What is the central question of this study? Does exercise affect vitaminD receptor expression in Tlymphocytes in young, middle-aged and older adults? What is the main finding and its importance? Moderate-intensity cycling exercise increases vitaminD receptor expression in vitaminD-deficient men, independent of age, presenting a strategy to combat the prevalence of vitaminD deficiency. Vitamin D plays a key role in the modulation of the immune system, mediated through the intracellular vitaminD receptor (VDR). Exercise has been shown to influence the activity and availability of the VDR. The aim of this study was to investigate the effect of age on basal immune cell (T-lymphocyte) VDR expression and the subsequent effect of acute aerobic exercise to modulate VDR expression in peripheral Tcells. Thirty-five men were included in the study (mean±SD: age 44±17years and body mass index 25.7±3.1kg/m2 ), separated into three age groups: 18-30 (n=12), 31-45 (n=11) and 60-75years (n=12). Participants completed two trials [control (CON) and aerobic exercise (AE)], with blood samples collected pre- and postexercise (0, 1 and 3 h). Peripheral blood Tcells were isolated and analysed for VDR expression by flow cytometry. The results show that advanced age is associated with lower VDR expression in Tcells (882±274, 796±243 and 594±174 geomean in the 18-30, 31-45 and 60-75year age groups, respectively). Acute AE was successful at acutely increasing VDR expression in Tcells, irrespective of age. Advanced age corresponds to a lower T-cell VDR expression, which might be responsible for age-associated development of chronic conditions and autoimmunity. Exercise was successful in increasing VDR expression in Tcells irrespective of age and independent of exercise-induced T-cell mobilization.