Summary: Women looking to reduce belly fat and blood pressure should exercise in the morning. Men who exercise at night showed improvements in metabolic and heart health, and improved overall emotional well-being.
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When should I include exercise in my daily schedule? For most, the answer depends on our family’s schedule and work schedule, and perhaps whether we are ‘larks’ or ‘night owls’. But over the past decade, researchers have discovered that much more hinges on this question than on these limitations. This is because recent findings suggest that the effectiveness of exercise depends on the time of day (Exercise Time Of Day, ETOD).
Now, a randomized controlled trial not only convincingly confirms that ETOD affects exercise effectiveness, but also shows that these effects differ between types of exercise and between women and men. The results are published in Frontiers in physiology.
Lead researcher Dr Paul J Arciero, a professor in the Department of Health and Human Physiological Sciences at Skidmore College in Saratoga Springs, New York, USA, said: “Here we show for the first time that for women, exercise in the morning reduces abdominal fat and blood pressure, while evening exercise in women increases muscle strength, power, and upper-body endurance, and improves overall mood and nutritional satiety.” .
“We also show that for men, evening exercise reduces blood pressure, heart disease risk, and feelings of fatigue, and burns more fat, compared to morning exercise.”
New 12-week ‘multimodal’ training program
The authors recruited 30 women and 26 men to participate. All were between 25 and 55 years old, healthy, very active, non-smokers and normal weight.
They were trained by trainers for 12 weeks, following the RISE program previously developed by Arciero et al.: Depending on the day of the week, 60 min of endurance training (R), sprint interval training (I), stretch training (S), or endurance training (E). Wednesdays, Saturdays and Sundays were days off.
The participants followed a specially designed eating plan with a protein intake of between 1.1 and 1.8 g per kg of body weight per day.
Importantly, male and female participants had been independently randomized beforehand to either of two regimens: training exclusively in the morning (60 minutes between 06:30 and 08:30) or in the evening (between 6:00 p.m. and 8:00 p.m.).
Those assigned to morning exercise ate breakfast after exercise and ate three more meals at four-hour intervals. Those assigned to evening exercise ate three meals at four-hour intervals before training, plus one afterward.
At the beginning and end of the trial, the participants were thoroughly tested for their aerobic power, muscular endurance, flexibility, balance, upper and lower body strength and power, and jumping ability. Only 16% of the 56 enrolled participants dropped out during the course of the 12-week trial, solely because they were unable to adhere to this nutrition and exercise program.
In addition to changes in the participants’ physical and metabolic parameters, such as blood pressure, arterial stiffness, respiratory exchange rate, and body distribution and percentage of fat during the trial, the researchers also measured changes in blood biomarkers eg insulin, total and ‘good’ HDL cholesterol, C-reactive protein and IL-6. They also administered questionnaires to the participants, to quantify changes in mood and feelings of food satiety.
Clear overall benefits of the program
The researchers show that all participants improved their overall health and performance over the course of the trial, regardless of their assignment to morning or evening exercise.
“Our study clearly demonstrates the benefits of both morning and evening multimodal exercise (RISE) for improving mood and cardiometabolic health, as well as physical performance outcomes in women and men,” said Arciero.
But crucially, they also show that ETOD determines the strength of improvements in physical performance, body composition, cardiometabolic health, and mood.
For example, all female participants reduced total body fat, abdominal and hip fat, and blood pressure during the test, but these improvements were greater in women who exercised in the morning. Only men who exercised at night showed a decrease in their total cholesterol to HDL ratio, blood pressure, respiratory exchange ratio, and carbohydrate oxidation, as fat became the preferred fuel source.
Different ETOD recommendations for women and men
“Based on our findings, women interested in reducing abdominal fat and blood pressure, while at the same time increasing leg muscle strength, should consider exercising in the morning. However, for women interested in gaining upper body muscular strength, power and endurance, as well as improving overall mood and food intake, evening exercise is the preferred option,” said Arciero.
“By contrast, evening exercise is ideal for men interested in improving heart and metabolic health, as well as emotional well-being.”
See also
Second author Stephen J Ives, Associate Professor at Skidmore College concluded: “We have shown that ETOD should be an important consideration for anyone, women and men, due to its effects on the physiological outcomes of exercise strength. But regardless of ETOD, regular exercise is essential to our health.”
About this exercise research news
Author: Mischa Dijkstra
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Contact: Mischa Dijkstra – Borders
Image: The image is in the public domain.
original research: Open access.
“Morning exercise reduces abdominal fat and blood pressure, and evening exercise increases muscle performance in women; while nighttime exercise increases fat oxidation and lowers blood pressure in men” by Paul J Arciero et al. Frontiers in physiology
Summary
Morning exercise reduces abdominal fat and blood pressure, and evening exercise increases muscle performance in women; while nighttime exercise increases fat oxidation and lowers blood pressure in men
Objective: Given known sex differences in response to exercise training, this study quantified health and performance outcomes in separate cohorts of women and men who adhered to different ETODs.
Methods: Thirty exercise-trained women (BMI = 24 ± 3 kg/mtwo; 42 ± 8 years) and twenty-six men (BMI = 25.5 ± 3 kg/mtwo; 45 ± 8 years) were randomized to multimodal ETOD in the morning (0600–0800 AM) or in the evening (1830–2030 PM) for 12 weeks and analyzed as separate cohorts. Base (week 0) and post (week 12) muscular strength (1-RM bench press/legs), endurance (abs/push-ups), and power (jump squats, SJ; bench throws, BT), body composition (Se evaluated iDXA, fat mass, FM, abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange ratio (RER), profile of mood states (POMS), and dietary intake.
Results: Twenty-seven women and twenty men completed the 12-week intervention. There were no differences at baseline between groups (AM vs PM) for the female and male cohorts. In women, significant interactions (p < 0.05) for 1RM bench (8 ± 2 vs. 12 ± 2, ∆kg), push-ups (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) PA, AM vs PM, respectively. In men, significant interactions (p < 0.05) for systolic BP (−3.5 ± 2.6 vs −14.9 ± 5.1, ∆mmHg), RER (−0.01 ± 0.01 vs −0.06 ± 0.01, ∆VCOtwo/OVtwo), and fatigue (−0.8 ± 2 vs −5.9 ± 2, ∆mm), AM vs PM, respectively. Macronutrient intake was similar between the AM and PM groups.
Conclusion: Morning exercise (AM) reduced abdominal fat and blood pressure, and evening exercise (PM) improved muscle performance in the female cohort. In the male cohort, PM increased fat oxidation and reduced systolic BP and fatigue. Therefore, ETOD may be important in optimizing individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.
