Evening Exercise Research Articles

A Single Night of Sleep Restriction Following Heavy Exercise Impairs Next-Morning 3-km Cycling Performance

Sufficient sleep (7-9 hr) is necessary for proper physiological function. Athletes are susceptible to sleep loss due to the physical demands of heavy training and the emotional stress of competition. A single night of sleep restriction does not appear to negatively impact next-morning performance. However, this has only been assessed with subjects in a well-rested training state. PURPOSE: The primary goal of this project was to examine recovery from of a single night of sleep restriction following heavy exercise on cycling time trial performance (TT) and skeletal muscle function in the morning. METHODS: Seven recreational cyclists (age, 24 ± 7 yr; VO2max, 62 ± 4 ml/kg/min) completed two phases, each consisting of an evening (EX1) and next-morning (EX2) exercise session. EX1 and EX2 were separated by an assigned sleep condition; a full night of rest (SLP+, 7.1 ± 0.3 hr of sleep) or sleep restriction through early waking (SLP−, 2.4 ± 0.2 hr). EX 1 consisted of baseline testing (muscle soreness, peak isokinetic torque at 120 deg/sec, a 20 min cycle ergometer warm-up, and subsequent 3-km TT performance) followed by heavy exercise that included 60 min of high intensity cycling intervals and resistance exercise. EX2 was performed to assess recovery from EX1, and included all baseline measures. Magnitude-based inferences were used to evaluate the effects of sleep condition on these measures. RESULTS:SLP− had a ‘very likely’ negative impact (96% likelihood) on the change in 3-km TT performance compared to SLP+. Specifically, 3-km TT performance was ‘very likely’ (99% LH) slower during EX2 compared to EX1 following SLP− (-4.0%), whereas TT performance was ‘possibly’ (54% LH) slower during EX2 (vs. EX1) following SLP+. Sleep condition did not influence the change in peak torque, as peak torque during EX2 was ‘likely’ lower than EX1 with both SLP+ (89% LH) and SLP− (80% LH). Likewise, sleep condition did not impact the change in muscle soreness, as muscle soreness ‘very likely’ increased from EX1 to EX2 with both SLP+ (97% LH) and SLP− (99% LH). CONCLUSION: A single night of sleep restriction following heavy exercise had marked consequences on 3-km TT performance the next morning. Strategies to ameliorate the consequences that sleep loss have on performance should be investigated.

Salivary cortisol concentration after high-intensity interval exercise: Time of day and chronotype effect

ABSTRACTDue to personal and working necessities, the time for exercise is often short, and scheduled early in the morning or late in the afternoon. Cortisol plays a central role in the physiological and behavioral response to a physical challenge and can be considered as an index of exercise stress. Therefore, the aim of this study was to evaluate the influence of the circadian phenotype classification on salivary cortisol concentration in relation to an acute session of high-intensity interval exercise (HIIE) performed at different times of the day. Based on the morningness–eveningness questionnaire, 12 M-types (N = 12; age 21 ± 2 years; height 179 ± 5 cm; body mass 74 ± 12 kg, weekly training volume 8 ± 1 hours) and 11 E-types (N = 11; age 21 ± 2 years; height 181 ± 11 cm; body mass 76 ± 11 kg, weekly training volume 7 ± 2 hours) were enrolled in a randomized crossover study. All subjects underwent measurements of salivary cortisol secretion before (PRE), immediately after (POST), and 15 min (+15 min), 30 min (+30 min), 45 min (+45 min) and 60 min (+60 min) after the completion of both morning (08.00 am) and evening (08.00 p.m.) high-intensity interval exercise. Two-way analysis of variance with Tuckey’s multiple comparisons test showed significant increments over PRE-cortisol concentrations in POSTcondition both in the morning (4.88 ± 1.19 ng · mL−1 vs 6.60 ± 1.86 ng · mL−1, +26.1%, P < 0.0001, d > 0.8) and in the evening (1.56 ± 0.48 ng · mL−1 vs 2.34 ± 0.37, +33.4%, P = 0.034, d > 0.6) exercise in all the 23 subject that performed the morning and the evening HIIE. In addition, during morning exercise, significant differences in cortisol concentration between M-types and E-types at POST (5.49 ± 0.98 ng · mL−1 versus 8.44 ± 1.08 ng · mL−1, +35%, P < 0.0001, d > 0.8), +15 min (4.52 ± 0.42 ng · mL−1 versus 6.61 ± 0.62 ng · mL−1, +31.6%, P < 0.0001, d > 0.8), +30 min (4.10 ± 1.44 ng · mL−1 versus 6.21 ± 1.60 ng · mL−1, +34.0%, P < 0.0001, d = 0.7), + 45 min (3.78 ± 0.55 ng · mL−1 versus 5.80 ± 0.72 ng · mL−1, +34.9%, P < 0.0001, d = 0.7), and + 60 min condition(3.53 ± 0.45 ng · mL−1 versus 5.78 ± 1.13 ng · mL−1, 38.9%, P = 0.0008, d = 0.7) were noted. No statistical significant differences between M-types and E-types during evening HIIE on post-exercise cortisol concentration were detected. E-types showed a higher morning peak of salivary cortisol respect to M-types when performing a HIIE early in the morning and produced higher salivary cortisol concentrations after the cessation of the exercise. Practical applications suggest that it is increasingly important for the exercise professionals to identify the compatibility between time of day for exercising and chronotype to find the individual’s favorable circadian time to perform a HIIE.

Effects of acute morning and evening exercise on subjective and objective sleep quality in older individuals with insomnia

ObjectivesThe aims of this study were to compare the effects of acute morning or evening exercise on nocturnal sleep in individuals with two subjective insomnia symptoms: difficulty in initiating sleep (DIS), and early morning awakening (EMA), separately for the first vs the second halves of the night. MethodsOlder individuals (55–65 years old) with DIS (N = 15) or EMA (N = 15) and age- and sex-matched controls (N = 13) participated in this non-randomized crossover study. Participants were assigned to two exercise conditions (morning exercise and evening exercise) in counterbalanced order following the baseline condition with a two-week interval between conditions. A single session of aerobic step exercise was performed during each exercise condition. Nocturnal polysomnography was carried out to evaluate objective sleep quality. Patient global impression of change scale scores for nocturnal sleep were obtained to subjectively evaluate the different groups. ResultsAcute physical exercise did not improve subjective sleep quality. Morning exercise decreased the number of stage shifts over the whole night. The arousal index and the number of stage shifts were decreased especially during the second half of the night in all groups. Furthermore, morning exercise decreased the number of wake stages during the second half of the night in the DIS group, but not in the EMA group. ConclusionsAcute morning exercise can improve nocturnal sleep quality in individuals with difficulty initiating sleep, especially during the later part of the night.

健康と生活習慣病予防における時間栄養学の役割

Almost all metabolic activities of nutrients are under control of the endocrine system, and among them the adrenocortical activity is the most typical example that shows circadian rhythmic changes. We examined relationships between the plasma corticosterone rhythm and feeding schedules in rats. The plasma corticosterone rhythm corresponding to feeding time appears regardless of whether the rats were kept on a light-dark cycle, or in constant light or were blinded. Therefore, it can be concluded that food, more than illumination, is a potent trigger of the circadian adrenocortical rhythm in rats. In addition to the experiments in rats, we also investigated roles of feeding schedulesinformation of the adrenocortical rhythm in human subjects. The corticosterone rhythm disappeared when rats were given a liquid diet intravenously, but not orally, suggesting a necessary role of the oro-gastro-intestinal tract. In addition to the studies in rats, influence to feeding schedules on adrenocortical rhythms was also examined in hospitalized human subjects under a normal light-dark cycle. A clear plasma cortisol rhythm was observed in patients who had been fed on a liquid diet into-duodenum during a restricted time of day, suggest that the circadian cortisol rhythm in man is more closely related to feeding rhythms than cycles of light-dark and sleep-wakefulness. As far as we know, this is the first report demonstrating the important of food in entraining human circadian cortisol rhythm. Next, we measured daily rhythm ofbody temperature in hospitalized patients under continuous and cyclic TEN（totalenteral nutrition）. In the diurnal TEN group, body temperature was low at night and early morning and high in the afternoon early evening. In the continuous TEN group, however, body temperature did not show any significant change with clock-time. In conclusion, the timing of diet intake remarkably modifies the circadian rhythm of body temperature and adrenocortical activity in man. We examined relationship between the feeding time of high salt diet intake and urinary excretion of sodium and chloride. The urinary excretion of sodium and chloride were higher in evening than morning and daytime in woman, is more closely related to the circadian plasma aldosterone rhythm. Furthermore, the clock time difference in endocrine and metabolic responses after physical exercise was assessed according to biorhythm. Physical capacity changed to the time of evaluation, and was greater in the evening than in the morning. Among physiological functions that determine was development of physical strength, plasma growth hormone was higher evening exercise than morning exercise. Further studies are needed on this intriguing idea.

The effect of consuming low- versus high-glycemic index meals after exercise on postprandial blood lipid response following a next-day high-fat meal

Background/Objectives:Exercise performed shortly before (that is, within half a day of) a high-fat meal is beneficial for stimulating fat oxidation after the meal and reducing postprandial triglycerides (TG). This benefit of exercise is unfortunately negated if the after-exercise food choice to replace the calories expended during exercise is one containing high-glycemic index (HGI) carbohydrates. We determined the effect of consuming low-glycemic index (LGI) carbohydrates after an exercise session on fat oxidation and TG after a subsequent high-fat meal.Subjects/Methods:Using a randomized, counterbalanced crossover design, 23 overweight or obese individuals (body mass index ⩾25 kg m−2) performed: walking exercise (90 min) at 1800 h followed by no meal (EX); exercise followed by a meal with LGI carbohydrates (that is, lentils, EX-LGI); exercise followed by a meal with HGI carbohydrates (that is, instant potatoes, white bread, EX-HGI); and a control condition with no exercise or meal. After a 10-h overnight fast, participants were given a standardized high-fat meal. Fat oxidation was estimated before and for 6 h after this meal from respiratory gas measures and TG determined from blood samples.Results:Fat oxidation (mean±s.d.) was higher with EX (6.9±1.7 g h−1) than EX-HGI (6.3±1.6 g h−1; P=0.007) and Control (5.9±1.7 g h−1; P=0.00002), and EX-LGI (6.6±1.7 g h−1) was higher than Control (P=0.002). TG total area under the curve was 18–32% lower with EX and EX-LGI compared with control (P=0.0005 and P=0.0001, respectively) and EX-HGI (P=0.05 and P=0.021, respectively).Conclusions:A meal containing HGI carbohydrates consumed after an evening exercise session cancels the beneficial effect of exercise for stimulating fat oxidation and lowering TG after a subsequent high-fat meal, whereas consuming a post-exercise meal with LGI carbohydrates retains the positive effect of exercise.

Shattered Obesity by Morning Eating and Evening Exercise

Shattered Obesity by Morning Eating and Evening Exercise

Effects of Low-Intensity Exercise in the Morning on Physiological Responses During Unsteady Workload Exercise in the Evening.

This study examined the effects of low-intensity morning exercise (ME) on physiological response during unsteady workload evening exercise. Nine healthy men participated in the following 2 experimental conditions: 15 minutes of bicycle exercise at 40% maximum oxygen consumption (V[Combining Dot Above]O2max) in the morning (the ME condition) and rest (control [C] condition). Heart rate (HR), blood pressure (BP), temperature, oxygen uptake, and natural logarithm of high frequency, an index of cardiac parasympathetic modulation, were measured before evening exercises, which were performed for 32 minutes in 2 parts: The steady-state exercise test included three 4-min bouts of exercise at 20, 60, and 40% V[Combining Dot Above]O2max. The unsteady exercise test consisted of 4-min bouts of exercise with gradual increases and decreases in workload at 20 and 60% V[Combining Dot Above]O2max. Heart rate, BP, and oxygen uptake were measured in both experiments. Maximal and minimal values, amplitude, and phase lags were measured with each cycle of unsteady workload exercise. With steady-state exercise, HR and systolic BP at 60 and 40% V[Combining Dot Above]O2max were significantly lower in the ME condition than in the C condition. However, oxygen uptake was not significantly different between the 2 conditions. With unsteady exercise, the HR and oxygen uptake phase lags were significantly shorter and the amplitude of oxygen intake was significantly larger in the ME condition than in the C condition. There were no significant differences in physiological parameters between the conditions at rest or during recovery. The physiological response during evening exercise is enhanced by low-intensity ME, which might be an effective conditioning method on a sporting event day.

The Effects of Evening Exercise Mode on Nocturnal Hypoglycemia During an Adult Diabetes Training Camp

Exercise is a cornerstone for diabetes management. Still, glycemic control has proven difficulty in exercisers with type 1 diabetes. While light to moderate aerobic and relaxation style exercise, like Yoga, frequently show reductions in glucose levels, anaerobic exercise can increase glucose due to its adrenergic effects. These responses may ensue both during and after the bout making treatment difficult and increasing risk of hypoglycemia, often occurring overnight. PURPOSE: To examine the effects of different exercise modes (Hatha Yoga versus Resistance Training) on the incidence of nocturnal hypoglycemia in adults with diabetes participating in a week long, high volume exercise training camp. METHODS: Adults with diabetes attending the 2015 Diabetes Training Camp™ were recruited to volunteer in this study. Participants were randomized to 1 of 3 groups: 1) Hatha Yoga (Y); Resistance Training Circuit (RT); or Non- exercise control (C). Each intervention group performed 45 minutes of evening exercise for 3 consecutive days. Data were collected through either electronic uploading using continuous glucose monitoring or self-reported monitoring. RESULTS: Twelve participants provided complete data to be analyzed (6 RT, 5 Y and 1 C). Demographics involved a mean age of 49.2±13 years; 83% female; 92% Caucasian; BMI=26.5±3.8 kg/m2; estimated VO2peak=36±7.4 ml/kg/min. Also, 75% of the adults were current exercisers with a mean of 4±2 days of hypoglycemic events per week. No significant differences were found between the groups. Overall, 41% of the study participants experienced at least one nocturnal hypoglycemic event (1 of 6 in RT; 3 of 5 Y; and 1 of 1 C) during the 3 day study. Those who participated in either the Y or C group were more likely to experience a nocturnal hypoglycemic event compared to the Resistance Training group (p= .068). Additionally, 40% of the Y group experienced nocturnal hypoglycemia on at least 2 of the 3 nights compared to only 16% in the RT group (p=.80). CONCLUSION: Performing RT in the evening, following a high volume of various exercise activities throughout the day, may reduce the incidence of nocturnal hypoglycemia. Future studies should examine additional exercise strategies, with larger samples, to reduce the barriers of hypoglycemia in adults exercising with diabetes.

Morning Eating and Evening Exercise: Towards an Anti-Cancer Lifestyle

This perspective article describes a methodology towards an anti-cancer lifestyle that involves morning and day-time eating complemented by evening exercise. This is a feasible practice that allows effective respiration and waste management by differential human cells.

Serum Klotho Levels in Trained Athletes.

Background:Klotho is an anti-aging protein that is predominantly secreted by the kidneys.Objectives:The aim of the study was to measure and compare the circulating Klotho levels in the serum of trained athletes and in healthy, non-athlete controls.Materials and Methods:Thirty trained football players were enrolled and their serum Klotho levels were measured the morning after their last evening exercise training.Results:The plasma free Klotho concentration was significantly higher in the athlete group (3.375 ± 1.48 ng/mL) compared to the non-athletes (1.39 ± 0.43 ng/mL) (P < 0.05). Serum levels of cholesterol, triglycerides, calcium, and phosphorus were not significantly different between the two groups.Conclusions:Regular aerobic exercise could increase plasma Klotho levels, and this could be an explanation for exercise-related anti-aging effects.

Evening Avoidance of Large Meals alongside Evening Exercise to Improve Maternal and Child Health

This perspective article describes a pragmatic methodology to improve mother and child health through reduced evening eating and increased evening exercise during gestation and lactation. Evening avoidance of large meals complemented by evening exercise, when insulin efficiency decreases helps pregnant and lactating mothers better cope with the changing endocrinology.

Effect of Breakfast Omission on Energy Intake and Evening Exercise Performance.

Breakfast omission may reduce daily energy intake. Exercising fasted impairs performance compared with exercising after breakfast, but the effect breakfast omission has on evening exercise performance is unknown. This study assessed the effect of omitting breakfast on evening exercise performance and within-day energy intake. Ten male, habitual breakfast eaters completed two trials in a randomized, counterbalanced order. Subjects arrived at the laboratory in an overnight-fasted state and either consumed or omitted a 733 ± 46 kcal (3095 ± 195 kJ) breakfast. Ad libitum energy intake was assessed at 4.5 h (lunch) and 11 h (dinner). At 9 h, subjects completed a 30-min cycling exercise at approximately 60% VO2peak, followed by a 30-min maximal cycling performance test. Food was not permitted for subjects once they left the laboratory after dinner until 0800 h the following morning. Acylated ghrelin, GLP-1(7-36), glucose, and insulin were assessed at 0, 4.5, and 9 h. Subjective appetite sensations were recorded throughout. Energy intake was 199 ± 151 kcal greater at lunch (P < 0.01) after breakfast omission compared with that after breakfast consumption and tended to be greater at dinner after consuming breakfast (P = 0.052). Consequently, total ad libitum energy intake was similar between trials (P = 0.196), with 24-h energy intake 19% ± 5% greater after consuming breakfast (P < 0.001). Total work completed during the exercise performance test was 4.5% greater after breakfast (314 ± 53 vs 300 ± 56 kJ; P < 0.05). Insulin was greater during breakfast consumption at 4.5 h (P < 0.05), with no other interaction effect for hormone concentrations. Breakfast omission might be an effective means of reducing daily energy intake but may impair performance later that day, even after consuming lunch.

Morning and evening physical exercise differentially regulate the autonomic nervous system during nocturnal sleep in humans.

Effects of daily physical exercise in the morning or in the evening were examined on circadian rhythms in plasma melatonin and core body temperature of healthy young males who stayed in an experimental facility for 7 days under dim light conditions (<10 lux). Sleep polysomnogram (PSG) and heart rate variability (HRV) were also measured. Subjects performed 2-h intermittent physical exercise with a bicycle ergometer at ZT3 or at ZT10 for four consecutive days, where zeitgeber time 0 (ZT0) was the time of wake-up. The rising phase of plasma melatonin rhythm was delayed by 1.1 h without exercise. Phase-delay shifts of a similar extent were detected by morning and evening exercise. But the falling phase shifted only after evening exercise by 1.0 h. The sleep PSG did not change after morning exercise, while Stage 1+2 sleep significantly decreased by 13.0% without exercise, and RE sleep decreased by 10.5% after evening exercise. The nocturnal decline of rectal temperature was attenuated by evening exercise, but not by morning exercise. HRV during sleep changed differentially. Very low frequency (VLF) waves increased without exercise. VLF, low frequency (LF), and high frequency (HF) waves increased after morning exercise, whereas HR increased after evening exercise. Morning exercise eventually enhanced the parasympathetic activity, as indicated by HRV, while evening exercise activated the sympathetic activity, as indicated by increase in heart rate in the following nocturnal sleep. These findings indicated differential effects of morning and evening exercise on the circadian melatonin rhythm, PSG, and HRV.

Post-Exercise Hypotension and Its Mechanisms Differ after Morning and Evening Exercise: A Randomized Crossover Study.

Post-exercise hypotension (PEH), calculated by the difference between post and pre-exercise values, it is greater after exercise performed in the evening than the morning. However, the hypotensive effect of morning exercise may be masked by the morning circadian increase in blood pressure. This study investigated PEH and its hemodynamic and autonomic mechanisms after sessions of aerobic exercise performed in the morning and evening, controlling for responses observed after control sessions performed at the same times of day. Sixteen pre-hypertensive men underwent four sessions (random order): two conducted in the morning (7:30am) and two in the evening (5pm). At each time of day, subjects underwent an exercise (cycling, 45 min, 50%VO2peak) and a control (sitting rest) session. Measurements were taken pre- and post-interventions in all the sessions. The net effects of exercise were calculated for each time of day by [(post-pre exercise)-(post-pre control)] and were compared by paired t-test (P<0.05). Exercise hypotensive net effects (e.g., decreasing systolic, diastolic and mean blood pressure) occurred at both times of day, but systolic blood pressure reductions were greater after morning exercise (-7±3 vs. -3±4 mmHg, P<0.05). Exercise decreased cardiac output only in the morning (-460±771 ml/min, P<0.05), while it decreased stroke volume similarly at both times of day and increased heart rate less in the morning than in the evening (+7±5 vs. +10±5 bpm, P<0.05). Only evening exercise increased sympathovagal balance (+1.5±1.6, P<0.05) and calf blood flow responses to reactive hyperemia (+120±179 vs. -70±188 U, P<0.05). In conclusion, PEH occurs after exercise conducted at both times of day, but the systolic hypotensive effect is greater after morning exercise when circadian variations are considered. This greater effect is accompanied by a reduction of cardiac output due to a smaller increase in heart rate and cardiac sympathovagal balance.

Evening Exercise to Prevent Central Adiposity and Cardiometabolic Diseases

The objective of this article was to develop a global guideline based on the necessity of evening exercise to improve insulin turnover and intermediary metabolism. Glucose intolerance develops as day leaves for evening and night. Designing public health programs that involve evening and early night exercise can induce insulin sensitivity and reduce cellular irresponsiveness to insulin, especially in overweight and obese people. This is a feasible approach to help overcome the many health issues caused or augmented by obesity and diabetes mellitus.

Insulin therapy and dietary adjustments to normalize glycemia and prevent nocturnal hypoglycemia after evening exercise in type 1 diabetes: a randomized controlled trial

IntroductionEvening-time exercise is a frequent cause of severe hypoglycemia in type 1 diabetes, fear of which deters participation in regular exercise. Recommendations for normalizing glycemia around exercise consist of prandial...

Effect Of Exercise And Glycemic Index Of Carbohydrate Feeding On Postprandial Fat Oxidation

Exercise performed shortly before (i.e. within half of day) of a high fat meal is beneficial for stimulating fat oxidation after the meal. This benefit of exercise is unfortunately negated if the after-exercise food choice to replace the calories expended during exercise is one containing high-glycemic index (HGI) carbohydrates . PURPOSE: We determined the effect of consuming low-glycemic index (LGI) carbohydrates after an exercise session on fat oxidation and free fatty acid (FFA) levels after a subsequent high fat meal. METHODS: Using a randomized, counter-balanced cross-over design, 23 overweight or obese individuals (BMI>25 kg/m2) performed: 1) Walking exercise (90min) at 6pm followed by no meal (EX); 2) Exercise followed by a meal with LGI carbohydrates (i.e. lentils, EX-LGI); 3) Exercise followed by a meal with HGI carbohydrates (i.e. potatoes, EX-HGI); 4) A control condition with no exercise or meal (CNT). In all conditions, after a 10 hour fast, participants were given a standardized high fat meal. Fat oxidation was estimated before, and for 6h after the meal from respiratory gas measures, and FFA was determined from blood samples. RESULTS: There was a condition main effect for fat oxidation (n=23) with EX (0.115 SD 0.033 g/min) higher than EX-HGI (0.105 SD 0.026 g/min) and CNT (0.099 SD 0.029 g/min) (p<0.05), and EX-LGI (0.110 SD 0.032) g/min) higher than CNT (p<0.05). There was a main effect for FFA, with greater FFA for EX-LGI (0.53 SD 0.08 mmol/L) and EX (0.52 SD 0.13 mmo/L) compared to EX-HGI (0.43 SD 0.07 mmol/L) and CNT (0.44 SD 0.06 mmol/L). There was no difference between EX-HGI and CNT for any measure. CONCLUSION: A meal containing HGI carbohydrates consumed after an evening exercise session cancels the beneficial effect of exercise for stimulating fat mobilization and oxidation after a subsequent high-fat meal. Consuming a post-exercise meal with LGI carbohydrates does not cancel this benefit and may therefore be more beneficial for maintaining metabolic health. Supported by the Heart and Stroke Foundation of Canada

Breakfast Omission Reduces 24 h Energy Intake and Evening Exercise Performance

Breakfast Omission Reduces 24 h Energy Intake and Evening Exercise Performance

Exercise Performed at Different Times of the Day Has Different Effects on Ambulatory Blood Pressure, Heart Rate and Arterial Stiffness

ObjectiveTo analyze ambulatory blood pressure (BP), heart rate and arterial stiffness responses after performing aerobic exercise in the morning and evening.Methods13 young pre‐hypertensive men underwent four experiments conducted in a random order: two at 9 am and two at 6:30 pm. At each time of day, a control and an exercise session (cycle ergometer 45 min, 50% VO2peak) were performed. After the sessions, ambulatory monitoring was performed for 24 hours taken measures each 15 minutes. Ambulatory systolic, diastolic and mean BP, as well as heart rate and arterial stiffness index were calculated for 24h, daytime and nighttime periods. At each time of day, data were compared between control and exercise sessions by a paired T‐test, p蠄0.05.ResultsAfter evening exercise, nighttime systolic BP was lower than the control session (116±11 vs. 120±10 mmHg, p=0.04). None of the other variables showed difference after evening exercise. After morning exercise, heart rate was greater than control for all periods (24h 80±7 vs. 76±6 bpm, p=0.02; daytime 83±8 vs. 79±7 bpm, p=0.01; and nighttime 72±8 vs. 67±5 bpm, p=0.05), and arterial stiffness was greater for 24h and daytime (0.298±0.098 vs. 0.233±0.068 U, p=0.01, and 0.432±0.137 vs. 0.322±0.089 U, p=0.02, respectively). None of the other variables showed differences after morning exercise.ConclusionAerobic exercise performed in the evening decreased nighttime BP while exercise performed in the morning increased heart rate and arterial stiffness. Financial support: CNPq: 472288/2011‐3, FAPESP: 2011/03584‐8.

The Effect of Caffeine Ingestion during Evening Exercise on Subsequent Sleep Quality in Females.

In a randomised, double-blind, placebo-controlled crossover design, 10 females taking monophasic oral contraceptives completed 90 min intermittent treadmill-running 45 min after ingestion of 6 mg∙kg(-1) body mass anhydrous caffeine or artificial sweetener (placebo). Water (3 mL∙kg(-1)) was provided every 15 min during exercise. Venous blood samples were taken before, during and after exercise, as well as after sleep (~15 h post-ingestion), and levels of caffeine, paraxanthine, theobromine and theophylline were measured using high-performance liquid chromatography. Sleep quality was assessed using the Leeds Sleep Evaluation Questionnaire. Plasma caffeine concentration peaked 100 min after ingestion. Caffeine clearance was 0.95±0.14 mL·min(-1)·kg(-1) while the elimination half-life of caffeine was 17.63±8.06 h. Paraxanthine and theophylline levels were significantly elevated at 15 h with no significant change in theobromine. Sleep latency and subsequent quality of sleep was impaired following caffeine supplementation (P<0.05); there were no differences between trials for how participants were feeling upon awakening. This is the first controlled study to examine caffeine supplementation on sleep quality in female athletes taking a low-dose monophasic oral contraceptive steroid following an intermittent-exercise running protocol. The data shows that female athletes using monophasic oral contraceptive steroids will have impaired sleep quality following evening caffeine ingestion.