It’s time to hit the gym – or is it? Will you have greater gains if you go first thing in the morning? Lose more weight if you sweat after work? Does time of day even matter?
Each individual has their own set of goals for their workouts. Maybe you want to get stronger, or faster, lose a few pounds or build endurance. Maybe your top priority is health maintenance and chronic disease prevention. Maybe you primarily want to use exercise as a stress reliever. Whatever your goal is, there is some mixed evidence that points towards different times of the day to achieve optimal results. WEIGHT
LOSS AND FAT REDUCTION
According to 2017–2018 data from the National Health and Nutrition Examination Survey (NHANES), nearly 1 in 3 adults (30.7%) are overweight, more than 2 in 5 adults (42.4%) are obese and about 1 in 11 adults (9.2%) have severe obesity. With approximately three quarters of our adult population carrying some extra pounds, weight loss (and in particular visceral fat) is a common expected outcome from exercise.
A study by Harvard Health found that morning workouts between 7:00 – 9:00 a.m. may help with obesity prevention and are associated with lower waist circumference and body mass index (BMI) compared to exercise later in the day. A 2019 study reported in the International Journal of Obesity found that those who exercised before noon were significantly more likely to lose 5% of their body weight (the amount that can have significant health improvement benefits) than those who worked out later in the day (an astonishing 81% versus 36%). A study performed at Skidmore College found that morning workouts burned more belly fat in women than evening ones (the results weren’t as clear for men).
BUILDING STRENGTH
If you’re looking to improve muscular strength, there is some evidence to suggest that late afternoon/evening may be the optimal time to workout. A 2022 systematic review and meta-analysis published by the National Library of Medicine indicates that grip strength is better during this time domain. A 2025 review by Augsberger et al. describes this phenomenon as a result of circadian body temperature rhythms, which typically peak in the late afternoon or early evening hours. The elevated core body temperature helps muscles contract more easily, providing better power output. A meta-analysis by Martin-Lopez et al. showed that neuromuscular performance (such as power output and agility) is better in the late afternoon or early evening hours.
IMPROVING ENDURANCE
Studies show that there is not an overall best time to workout to improve endurance. However, if you are training for a race or other endurance-type event, a 2023 systematic review by Bruggisser et al. shows that you will have a performance peak if the event is at the same time of day that you’ve been consistently training. For example, if you are training for a marathon and it starts at 7 a.m., complete as many training runs in that same time window as you can for an edge on race day.
IMPROVING BIOMETRIC MEASURES FOR METABOLIC SYNDROME
Struggling to get a handle on metabolic syndrome? A randomized controlled trial by Morales-Palomo et al. assigned participants to an intense aerobic exercise program either in the morning, evening or no exercise. They found that both of the exercise groups had improved biometrics but that the morning group more significantly decreased their systolic blood pressure and insulin sensitivity.
STRESS AND ANXIETY
The studies on the timing of exercise for stress and anxiety relief are mixed. Exercise is a great stress reliever so it will help no matter what time of day you do it. A 2019 study in the Journal of Obesity states that morning workouts will help reduce adrenaline and boost mood early in the day, leading to a more protective and calm effect throughout the day. The Cleveland Clinic says that afternoon/evening workouts can help relieve stress at the end of the workday as well as avoiding the stress of having to rush (to be finished and at work on time in the morning).
GENERAL HEALTH BENEFITS
A study by Feng et al. of over 90,000 individuals over seven years found that those who routinely completed moderate to vigorous intensity exercise between 11 a.m. – 5 p.m. had lower risk of all-cause mortality and cardiovascular disease risk mortality. This time frame may also be best for general health due to the peak in core body temperature, allowing for better muscle contraction.
