Summary: Women looking to reduce belly fat and blood pressure should exercise in the morning. Men who exercised in the evening showed improvements in metabolic and heart health, and improved overall emotional well-being.
When should I exercise in my daily schedule? For the most part, the answer depends on our family’s schedule and work hours, and perhaps whether we are “larks” or “night owls.” But over the past decade, researchers have discovered that this issue is not limited to these constraints. Indeed, 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 efficacy, but also shows that these effects differ between exercise types and between women and men. The results are published in Frontiers in Physiology.
Lead researcher Dr Paul J Arciero, Professor in the Department of Health Sciences and Human Physiology at Skidmore College in Saratoga Springs, NY, USA, said: “Here we show for the first time that for women, morning exercise reduces belly fat and blood pressure, while evening exercise in women increases upper body muscle strength, power and 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 than morning exercise.”
New 12-week “multimodal” training program
The authors recruited 30 women and 26 men to participate. All were between the ages of 25 and 55, in good health, very active, non-smokers and of normal weight.
They were trained by coaches for 12 weeks, following the RISE program previously developed by Arciero et al.: depending on the day of the week, either 60 min of resistance training (R), sprint interval training (I), stretching training (S) or endurance training (E) ). Wednesdays, Saturdays and Sundays were rest days.
The participants followed a specially designed meal plan with a protein intake of between 1.1 and 1.8 g per kg of body weight per day.
Importantly, female and male participants were previously randomized independently to one of two regimens: training exclusively in the morning (60 min between 6:30 a.m. and 8:30 a.m.) or in the evening (between 6:00 p.m. and 8:00 p.m.).
Those assigned to morning exercise ate breakfast after exercise and had three more meals four hours apart. Those assigned to evening exercise ate three meals four hours apart before training, plus one after.
At the start and end of the trial, participants were thoroughly assessed for aerobic power, muscular endurance, flexibility, balance, upper and lower body strength and power, and ability to skip. Only 16% of the 56 enrolled participants dropped out during the 12-week trial, exclusively because they were unable to stick to this nutrition and exercise program.
In addition to changes in participants’ physical and metabolic parameters such as blood pressure, arterial stiffness, respiratory exchange rate, body distribution, and fat percentage during the trial, the researchers also measured changes in relevant blood biomarkers, eg insulin, total and ‘good’ HDL cholesterol, C-reactive protein and IL-6. They also administered questionnaires to the participants, to quantify mood changes and feelings of food satiety.
Clear overall program benefits
The researchers show that all participants improved their overall health and performance during the trial, regardless of whether they were assigned to morning or evening exercise.
“Our study clearly demonstrates the benefits of morning and evening multimodal exercise (RISE) to improve mood and cardiometabolic health, as well as exercise performance in women and men,” Arciero said.
Importantly, they also show that ETOD determines the strength of improvements in exercise performance, body composition, cardiometabolic health, and mood.
For example, all participants reduced their total body fat, abdominal and hip fat, and blood pressure during the trial, but these improvements were greater in women who exercised in the morning. Only men exercising in the evening showed a decrease in their ratio of total cholesterol to HDL, blood pressure, respiratory exchange rate, and carbohydrate oxidation, as fat became the fuel source favourite.
Different ETOD recommendations for women and men
“Based on our findings, women interested in reducing belly fat and blood pressure, while increasing leg muscle power, should consider exercising in the morning. However, women interested in gaining strength, power and endurance in upper body muscles, as well as improving overall mood and food intake, evening exercise is the preferred choice,” Arciero said.
“Conversely, evening exercise is ideal for men who want to improve their heart and metabolic health, as well as their emotional well-being.”
Second author, Stephen J Ives, Associate Professor at Skidmore College, concluded: “We have shown that ETOD should be an important consideration for all, women and men, given its effects on the strength of physiological outcomes of the ‘exercise. But regardless of ETOD, regular exercise is essential for our health.
About this exercise research news
Author: Mischa Dijkstra
Contact: Mischa Dijkstra – Borders
Image: Image is in public domain
Original research: Free access.
“Morning exercise reduces abdominal fat and blood pressure and evening exercise increases muscle performance in women; while evening exercise increases fat oxidation and lowers blood pressure in men” by Paul J Arciero et al. Frontiers in Physiology
Morning exercise reduces abdominal fat and blood pressure and evening exercise increases muscle performance in women; while evening 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 adhering to different ETODs.
Methods : Thirty exercise-trained women (BMI = 24 ± 3 kg/m2; 42 ± 8 years old) and twenty-six men (BMI = 25.5 ± 3 kg/m2; 45 ± 8 years) were randomized to receive multimodal ETOD in the morning (0600–0800 h, AM) or evening (1830–2030 h, PM) for 12 weeks and analyzed in separate cohorts. Core muscle strength (Week 0) and post (Week 12) (1-RM press/leg press), endurance (sit-ups/push-ups) and power (squat jumps, SJ; bench throws, BT), composition (iDXA; fat mass, FM; abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange rate (RER), profile of mood states (POMS), and food intake were assessed.
Results: Twenty-seven women and twenty men completed the 12-week intervention. No difference at baseline existed between the groups (AM vs PM) for the female and male cohorts. In women, important interactions (p p 2/OV2), 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 (AM) exercise reduced abdominal fat and blood pressure and evening (PM) exercise improved muscle performance in the female cohort. In the male cohort, PM increased fat oxidation and reduced systolic pressure and fatigue. Thus, ETOD may be important in optimizing individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.