Time Of Day Exercise Research Articles

Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial.

A supervised intense aerobic exercise program improves the health of individuals with metabolic syndrome (MetS). However, it is unclear whether the timing of training within the 24h day would influence those health benefits. The present study aimed to determine the influence of morning vs. afternoon exercise on body composition, cardiometabolic health and components of MetS. One hundred thirty-nine individuals with MetS were block randomized into morning (AMEX; n=42) or afternoon (PMEX; n=59) exercise training groups, or a non-training control group (Control; n=38). Exercise training was comprised of 48supervised high-intensity interval sessions distributed over 16weeks. Body composition, cardiorespiratory fitness (assessed by ), maximal fat oxidation (FOmax ), blood pressure and blood metabolites were assessed before and after the intervention. Compared with the non-training Control, both exercise groups improved similarly body composition (-0.7% fat loss; P=0.002), waist circumference (-2.1 cm; P<0.001), diastolic blood pressure (-3.8mmHg; P=0.004) and (3.5mLkg-1 min-1 ; P<0.001) with no differences between training groups. AMEX, in comparison with PMEX, reduced systolic blood pressure (-4% vs. -1%; P=0.019), plasma fasting insulin concentration (-12% vs. -5%; P=0.001) and insulin resistance (-14% vs. -4%; P=0.006). Furthermore, MetS Zscore was further reduced in the AMEX compared to PMEX (-52% vs. -19%; P=0.021) after training. In summary, high-intensity aerobic exercise training in the morning in comparison to training in the afternoon is somewhat more efficient at reducing cardiometabolic risk factors (i.e. systolic blood pressure and insulin sensitivity). KEY POINTS: The effect of exercise time of day on health promotion is an area that has gained interest in recent years; however, large-scale, randomized-control studies are scarce. People with metabolic syndrome (MetS) are at risk of developing cardiometabolic diseases and reductions in this risk with exercise training can be precisely gauged using a compound score sensitive to subtle evolution in each MetS component (i.e. Z score). Supervised aerobic exercise for 16weeks (morning and afternoon), without dietary restriction, improved cardiorespiratory and metabolic fitness, body composition and mean arterial pressure compared to a non-exercise control group. However, training in the morning, without changes in exercise dose or intensity, reduced systolic blood pressure and insulin resistance further compared to when training in the afternoon. Thus, high-intensity aerobic exercise training in the morning is somewhat more efficient in improving the health of individuals with metabolic syndrome.

Timing of Exercise Among Young Adults Previously Enrolled in a Randomized Controlled Weight Management Trial: An Observational Study

This study examined self-reported exercise time of day and psychosocial/behavioral correlates in a cohort of young adults previously enrolled in a randomized controlled weight management trial. An online survey was distributed to participants of the trial 2 years after conclusion. Questions assessed physical activity (PA), PA self-efficacy, sleep parameters, and BMI. One item assessed exercise timing: “During the last 7 days, I tended to exercise in the…” Response options included: Early morning (04:00-08:59 am), Mid-morning (09:00-11:59 am), Afternoon (12:00-04:59 pm), Evening (05:00 pm-3:59 am), varied times, or no exercise. Differences in baseline or follow-up characteristics were examined across exercise time using Fisher’s Exact and Kruskal–Wallis tests. Of 107 participants contacted, 38 responded, and 31 provided eligible responses. Evening exercise was most frequently reported (N = 11), followed by varied times (N = 10), early morning (N = 4), mid-morning (N = 4), and afternoon (N = 2). PA self-efficacy was highest in evening exercisers (16.1 ± 2.6) compared with those exercising at other times ( P = .015). Moderate-to-vigorous PA was also highest in evening exercisers (265.0 ± 123.1 min/week) compared with those exercising at other times ( P = .035). Pending evidence from larger observational studies, evening may be a relatively popular time to exercise among young adults, and may be associated with greater PA self-efficacy and weekly PA.

Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men.

The ideal exercise time of day (ETOD) remains elusive regarding simultaneous effects on health and performance outcomes, especially in women. Purpose: Given known sex differences in response to exercise training, this study quantified health and performance outcomes in separate cohorts of women and men adhering to different ETOD. Methods: Thirty exercise-trained women (BMI = 24 ± 3 kg/m2; 42 ± 8 years) and twenty-six men (BMI = 25.5 ± 3 kg/m2; 45 ± 8 years) were randomized to multimodal ETOD in the morning (0600–0800 h, AM) or evening (1830–2030 h, PM) for 12 weeks and analyzed as separate cohorts. Baseline (week 0) and post (week 12) muscular strength (1-RM bench/leg press), endurance (sit-ups/push-ups) and power (squat jumps, SJ; bench throws, BT), body composition (iDXA; fat mass, FM; abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange ratio (RER), profile of mood states (POMS), and dietary intake were assessed. Results: Twenty-seven women and twenty men completed the 12-week intervention. No differences at baseline existed between groups (AM vs PM) for both women and men cohorts. In women, significant interactions (p < 0.05) existed for 1RM bench (8 ± 2 vs 12 ± 2, ∆kg), pushups (9 ± 1 vs 13 ± 2, ∆reps), BT (10 ± 6 vs 45 ± 28, ∆watts), SJ (135 ± 6 vs 39 ± 8, ∆watts), fat mass (−1.0 ± 0.2 vs −0.3 ± 0.2, ∆kg), Abfat (−2.6 ± 0.3 vs −0.9 ± 0.5, ∆kg), diastolic (−10 ± 1 vs−5 ± 5, ∆mmHg) and systolic (−12.5 ± 2.7 vs 2.3 ± 3, mmHg) BP, AM vs PM, respectively. In men, significant interactions (p < 0.05) existed for systolic BP (−3.5 ± 2.6 vs −14.9 ± 5.1, ∆mmHg), RER (−0.01 ± 0.01 vs −0.06 ± 0.01, ∆VCO2/VO2), and fatigue (−0.8 ± 2 vs −5.9 ± 2, ∆mm), AM vs PM, respectively. Macronutrient intake was similar among AM and PM groups. Conclusion: Morning exercise (AM) reduced abdominal fat and blood pressure and evening exercise (PM) enhanced muscular performance in the women cohort. In the men cohort, PM increased fat oxidation and reduced systolic BP and fatigue. Thus, ETOD may be important to optimize individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.

Glucocorticoids differentially regulate the skeletal muscle transcriptome in response to acute aerobic exercise at distinct times of day

Adaptations to the skeletal muscle following long term aerobic exercise training are mediated at least in part by transcriptional changes that occur in response to each bout of exercise. There is evidence that glucocorticoids induce transcriptional changes in the skeletal muscle in response to a bout of aerobic exercise, but the extent of these changes and whether time of day exercise affects the glucocorticoid transcriptional response is unknown. The purpose of this study was to define changes to the skeletal muscle glucocorticoid transcriptome in response to acute aerobic exercise at different times of day. A secondary purpose was to define the role of Regulated in Development and DNA Damage 1 (REDD1) in mediating these changes as REDD1 is not only a transcriptional target of the glucocorticoid receptor, but it can also modulate glucocorticoid receptor transcriptional activity. A list of glucocorticoid target genes whose expression is altered in the skeletal muscle at various times of day in response to acute exercise was generated by comparing published genomic data sets from rodents subjected to acute aerobic exercise in the light or dark cycles to published genomic data sets from C2C12 myotubes treated with Dexamethasone. The role of glucocorticoid receptor signaling to the genomic changes was assessed in exercised mice treated with RU‐486. The role of REDD1 in mediating the changes to the glucocorticoid transcriptome was assessed in mice lacking REDD1. Glucocorticoids modulated expression of numerous genes in the skeletal muscle in response to acute aerobic exercise in the light and dark cycles, including those that are a target of, or contribute to, ubiquitin conjugation. The extent of changes to the glucocorticoid transcriptome was greater when exercise was conducted in the dark cycle compared to the light cycle. Only some genes encoding proteins involved in ubiquitin conjugation were induced by exercise at both times of day. REDD1 is required for the induction of these genes, whereas those only induced in the light cycle did not require REDD1. The time of day at which aerobic exercise is conducted dictates the extent of changes to the glucocorticoid transcriptome in skeletal muscle. REDD1 is a transducer mediating the time‐of‐day changes to the glucocorticoid transcriptome in skeletal muscle.

Influence of Exercise Time of Day on Salivary Melatonin Responses.

Sleep deprivation negatively affects cognition, pain, mood, metabolism, and immunity, which can reduce athletic performance. Melatonin facilitates sleepiness and may be affected by the proximity of exercise to sleep. To evaluate the influence of exercise time of day on salivary melatonin (s-melatonin) responses. Twelve regularly exercising men (age 20.75 [0.62]y, height 1.75 [0.04]m, mass 73.63 [10.43]kg, and maximal oxygen consumption 57.72 [6.11]mL/kg/min) participated in a randomized, crossover design. Subjects completed 3 protocols-morning exercise (09:00h), afternoon exercise (16:00h), and no exercise (CON)-at least 5 d apart. Exercise sessions consisted of 30min of steady-state running at 75% of maximal oxygen consumption. Saliva was collected via passive drool at 20:00, 22:00, and 03:00h following all sessions. Repeated-measures analysis of variance revealed significant time (P = .001) and condition (P = .026) effects for melatonin. Levels of s-melatonin were significantly increased at 03:00h compared with 20:00 and 22:00h for all conditions. Post hoc analyses revealed that s-melatonin at 22:00 h was significantly higher after morning exercise (16.5 [7.5]pg/mL) compared with afternoon exercise (13.7 [6.1]pg/mL) sessions (P = .03), whereas neither exercise condition significantly differed from the control (P > .05). It appears that exercising in the afternoon may blunt melatonin secretion compared with morning exercise. If sleep is an issue, morning exercise may be preferable to afternoon exercise.

Self-paced aerobic exercise performed in the morning versus the evening: Is there a difference in exercise intensity?

Background: Exercise performance can be affected by time of day, but it is unknown whether there are subsequent physiological adaptations or health implications. These data provide preliminary findings from a large randomised controlled trial investigating exercise time of day on body composition and health outcomes. A key facet of the trial is to identify if time of day (morning or evening) influences exercise intensity and/or if getting matched according to your chronotype or preference influences exercise intensity during the sessions.

Influence of Exercise Time of Day on Salivary Melatonin Responses

Sleep deprivation may have changes in cognition, pain, mood, metabolism, and immunity, which can ultimately create negative consequences on athletic performance. Melatonin is thought to induce sleepiness due to its synchronization with the circadian rhythm. PURPOSE: The purpose of this study was to evaluate the influence of exercise time of day on salivary melatonin (s-Mel) responses. METHODS: Ten regularly exercising, males (age 20.7 ± 0.7 yr; height 1.74 ± 0.04 m, mass 73.6 ± 11.4 kg, maximal oxygen consumption [VO2max] 56.4 ± 4.4 ml/kg/min-1) completed a VO2max using an incremental protocol on a treadmill. In a randomized, crossover design, subjects completed three protocols: morning exercise (09:00 h), afternoon exercise (16:00 h), and no exercise (control) at least 5 days apart. For each exercise session, subjects performed 30 min of steady-state running at 75% of VO2max following a 5 min warm-up. Saliva was collected via a passive drool into 2 ml polypropylene conical tubes at 20:00 h, 22:00 h, and 03:00 h following all sessions. RESULTS: No significant differences existed in the s-Mel levels for exercise time of day. A trend found morning exercise produced a higher concentration of s-Mel than afternoon exercise (p = 0.074). The 20:00 h collection time was significantly higher than the 03:00 h collection (p = 0.001). Additionally, s-Mel levels were significantly (p = 0.018) greater for the 20:00 h collection time compared to the 22:00 h collection, and 22:00 h was greater than 03:00 h (p = 0.038). CONCLUSION: It appears that exercise time of day did not affect s-Mel levels.Table 1: s-Mel Levels, (pg/mL), Mean ± SDSupported by: NEACSM Undergraduate Research Grant

Diurnal variation in the salivary melatonin responses to exercise: relation to exercise-mediated tachycardia

Salivary melatonin concentration is an established marker of human circadian rhythmicity. It is thought that melatonin is relatively robust to the masking effects of exercise. Nevertheless, the extent and even the direction of exercise-related change is unclear, possibly due to between-study differences in the time of day exercise is completed. Therefore, we aimed to compare melatonin responses between morning and afternoon exercise, and explore the relationships between exercise-related changes in melatonin and heart rate. At 08:00 and 17:00hours, seven male subjects (mean±SD age, 27±5years) completed 30min of cycling at 70% peak oxygen uptake followed by 30min of rest. Light intensity was maintained at ~150lx. Salivary melatonin (ELISA) and heart rate were measured at baseline, 15min during exercise, immediately post-exercise and following 30min recovery. Melatonin was ≈15pgml(-1) higher in the morning trials compared with the afternoon (P=0.030). The exercise-related increase in melatonin was more pronounced (P=0.024) in the morning (11.1±8.7pgml(-1)) than in the afternoon (5.1±5.7pgml(-1)). The slope of the heart rate-melatonin relationship was significantly (P=0.020) steeper in the morning (0.12pgml(-1)beats(-1)min(-1)) than in the afternoon (0.03pgml(-1)beats(-1)min(-1)). In conclusion, we report for the first time that the masking effect of moderate-intensity exercise on melatonin is approximately twice as high in the morning than the afternoon. The much steeper relationship between heart rate and melatonin changes in the morning raises the possibility that time of day alters the relationships between exercise-mediated sympathetic nervous activity and melatonin secretion.

Lack of Effect of Exercise Time of Day on Acute Energy Intake in Healthy Men

Although the manipulation of exercise and dietary intake to achieve successful weight loss has been extensively studied, it is unclear how the time of day that exercise is performed may affect subsequent energy intake. The purpose of the current study was to investigate the effect of an acute bout of exercise performed in the morning compared with an equivalent bout of exercise performed in the afternoon on short-term energy intake. Nine healthy male participants completed 3 trials: morning exercise (AM), afternoon exercise (PM), or control (no exercise; CON) in a randomized counterbalanced design. Exercise consisted of 45 min of treadmill running at 75% VO(2peak). Energy intake was assessed over a 26-hr period with the participants eating ad libitum from a standard assortment of food items of known quantity and composition. There was no significant difference in overall energy intake (M ± SD; CON 23,505 ± 6,938 kJ, AM 24,957 ± 5,607 kJ, PM 24,560 ± 5,988 kJ; p = .590) or macronutrient preferences during the 26-hr period examined between trials. Likewise, no differences in energy intake or macronutrient preferences were observed at any of the specific individual meal periods examined (i.e., breakfast, lunch, dinner) between trials. These results suggest that the time of day that exercise is performed does not significantly affect short-term energy intake in healthy men.

Effect of exercise time of day on energy intake in normal weight males

Introduction: Although the manipulation of exercise and dietary intake to achieve successful weight loss has been extensively studied, the effect of exercise itself on energy intake is not well understood. The purpose of this study was to investigate the effect of the time of day that exercise is performed (morning compared to afternoon) on short-term energy intake. Methodology: Nine healthy male participants completed three trials; morning exercise, afternoon exercise and control (no exercise) in a random crossover design.

The effects of acute and chronic exercise on sleep. A meta-analytic review.

Studies attempting to ascertain the effects of acute and chronic exercise on measures of sleep have yielded conflicting results and interpretations. Methodological differences among studies may explain this lack of consensus; however, small sample sizes and subsequently low statistical power may also have contributed. In an attempt to resolve these issues, this review used meta-analytical techniques to: (a) re-examine the effects of exercise on sleep; and (b) examine possible moderators of these effects. Studies meeting the selection criteria were included in the analysis. Analyses of moderating factors were performed for stage 4 sleep and rapid eye movement (REM) sleep. The results indicated that acute and chronic exercise increased slow wave sleep (SWS) and total sleep time but decreased sleep onset latency and REM sleep. Moderating variables influencing the magnitude and direction of these effects were related to characteristics of the individual (e.g. sex, age, fitness level) and the exercise (e.g. time of day exercise was completed, type of exercise, exercise duration). Mechanisms which have been suggested to explain the relationship between exercise and sleep are discussed and directions for further research are provided.

Effects of exercise intensity, duration, and time of day on fibrinolytic activity in physically active men

The purposes of this investigation were to determine: 1) whether the fibrinolytic responses to acute, submaximal exercise were best related to intensity, duration, or total caloric expenditure; and 2) whether the time of day exercise is performed affects the fibrinolytic response. Twelve physically active men (mean age = 34.8 +/- 4.0 yr) performed four 30-min exercise sessions: 50% VO2max, a.m. and p.m., and 80% VO2max, a.m. and p.m. Blood samples were analyzed for tissue plasminogen activator (TPA) activity and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a three-way ANOVA with repeated measures. TPA activity: preexercise TPA did not differ among the four sessions. TPA increased with exercise in all sessions except the 50% a.m. session. Exercise at 80% increased TPA more than 50% (P < 0.001) and evening sessions increased TPA more than morning sessions (P < 0.05). PAI-1 activity: preexercise PAI-1 activity was higher during the morning than evening and significantly decreased with exercise in all sessions except the 50% p.m. session. It was concluded that changes in fibrinolytic activity appear to be influenced primarily by exercise intensity rather than duration or total caloric expenditure. Additionally, time of day of exercise performance significantly influenced fibrinolytic activity.