For the first time, researchers have shown that the best time of day to exercise varies depending on a person’s gender and exercise goals.
When should I adjust to my regular exercise routine? The answer is often influenced by our family schedules, work hours, and perhaps whether we are “night owls” or “night owls.” However, over the past decade, researchers have discovered that this question is much more important than these limitations. That’s because new research shows that the time of day (Ercise Time Of Day, ETOD) can affect how beneficial exercise is.
Now, randomized controlled trials show that ETOD affects exercise performance, and that these effects differ across exercise types and between women and men. The results were recently published in the journal Frontiers in Physiology.
Chief investigator Dr. Paul 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 morning exercise in women reduces abdominal fat and blood pressure. Evening exercises for women increase upper body muscle strength and endurance, as well as improve overall mood and nutrition.
“We also show that for men, evening exercise reduces blood pressure, heart disease risk, fatigue, and burns more fat compared to morning exercise.”
A new 12-week “multimodal” training program
30 women and 26 men applied for help. All were healthy, physically active, non-smokers, and of normal weight between the ages of 25 and 55 years. They were trained by trainers for 12 weeks using the RISE program developed by Arciero et al.: either 60 min of resistance (R) training, sprint interval (I) training, stretching (S) training, or endurance (E) training, depending on the day of the week. Days off were Wednesday, Saturday and Sunday. The participants followed a carefully designed diet plan containing 1.1 to 1.8 g of protein per kg of body weight per day.
Importantly, female and male participants were randomly assigned to one of two regimens: morning exercise (60 minutes between 06:30 and 08:30) or evening exercise (18:00 and 20:00). Morning exercises were divided into three meals at four-hour intervals before breakfast immediately after exercise. Nocturnal eaters eat three meals at four-hour intervals before training, followed by one more.
At the beginning and end of the trial, participants were comprehensively assessed for aerobic power, muscular endurance, flexibility, balance, upper and lower body strength and power, and jumping ability. Of the 56 participants enrolled, only 16% dropped out during the 12-week trial due to inability to maintain this diet and exercise schedule.
The researchers compared the changes in physical and metabolic parameters of the participants, such as blood pressure, arterial stiffness, respiratory exchange ratio and body distribution and fat percentage, to changes in relevant blood biomarkers, such as insulin, total and “good” HDL cholesterol, C-reactive protein and IL-6. They also administered questionnaires to participants to quantify changes in mood and feelings of satiety.
Clear overall benefits of the program
The researchers found that regardless of whether they were assigned to exercise in the morning or in the evening, the health and performance of all participants improved over the course of the trial.
“Our study clearly demonstrates the benefits of morning and evening multimodal exercise (RISE) for improving cardiometabolic and mood health as well as physical performance in women and men,” said Arciero.
But more importantly, they show that ETOD leads to improvements in physical performance, body composition, cardiometabolic health, and mood.
For example, all female participants in the trial reduced total body fat, abdominal and hip fat, and blood pressure, but these improvements were greater in women who exercised in the morning. Only the men who exercised in the evening showed reductions in their HDL cholesterol 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 increasing leg muscle strength should consider exercising in the morning. However, for women interested in improving upper body strength, power and endurance, as well as overall mood and nutrition, evening exercise is the preferred choice,” said Arciero.
“On the contrary, evening exercise is ideal for men interested in improving heart and metabolic health, as well as emotional well-being.”
Second author Stephen J. Ives, associate professor at Skidmore College, said: “We have shown that ETOD should be something important for everyone, women and men, given its impact on the physiological effects of exercise. But regardless of ETOD, regular exercise is essential for our health.”
Reference: “Morning exercise reduces belly fat and blood pressure in women; Evening Exercise Increases Muscle Performance in Women and Lowers Blood Pressure in Men” by Paul J. Arciero1, Steven J. Ives, Alex E. Mohr, Nathaniel Robinson, Daniela Escudero, Jake Robinson, Kayla Rose, Olivia Minicucci, Gabriel O’Brien, Katherine Curran, Vincent J. Miller, Feng He, Chelsea Norton, Maya Paul, Caitlin Sheridan, Sheridan Beard, Jessica Centor, Monique Dudar, Katie Enstrom, Duckembay Hoyt, Heather Mack, and Aaliyah Yard, 31 May 2022, Frontiers in Physiology.
The study was funded by Isagenix International, LLC.