By Jack Harley, MSc, University of Oxford
Making time to exercise on a regular basis can be challenging, and usually finding any time to exercise is the most important thing. But if you want to get the most out of your workouts, when you exercise may also be important.
Regardless of the timing, there are many benefits of working out such as improved endurance and strength, lower blood pressure and decreased risk of chronic diseases such as type 2 diabetes.
However, choosing an appropriate time to exercise can boost physical performance, help with sleep, and improve your circadian rhythm. In many cases, finding the ideal time to workout can be as much about personal preference than about physiology.
The advantages of working out in the morning compared to the afternoon or evening are discussed in this article.
Table of Contents
Working out in the morning
There are many benefits of working out in the morning. For the early birds, working out in the morning can be a preferred time, and may be associated with the following benefits:
Increased fat loss
Research has shown that you burn more body fat on an empty stomach. Therefore, exercising before breakfast may allow you to burn more fat than exercising later in the day. However, the benefit of this form of ‘fasted cardio’ may only last a short period.
Over the course of weeks or months, studies have shown that fat loss with or without having eaten a meal was the same. For example, one study randomly assigned women to receive either a 250-calorie shake or to fast before an aerobic workout, and fat loss was the same for both groups.
Better sleep
Working out in the morning may lead to better sleep than working out in the afternoon or evening. One study in endurance athletes showed that those who exercised in the morning tended to sleep better by spending less time lying awake in bed than those who worked out in the evening. However, the research is not definitive, as some research has shown that evening exercise may also improve sleep.
Improved circadian rhythm
Working out in the morning shifts your body clock earlier, meaning you will likely feel tired earlier, and wake up earlier the next day. This may help to align your circadian rhythm more closely with daylight hours.
Easier to build a routine
Morning workouts may be easier to stick to. Research suggests that healthy habits in the morning are easier to maintain over a long period of time than those later in the day. This may be because many people generally have fewer commitments in the morning compared to later in the day. For example, one study showed that exercise adherence was slightly higher in individuals who worked out in the morning, compared to the afternoon.
Improved pain management
Another benefit of working out in the morning is that it may help in managing chronic pain. Research has demonstrated that morning workouts are more effective in reducing bodily pain than evening workouts.
Improved productivity during the day
Working out triggers the release of hormones known as endorphins that uplift your mood, which can make you more productive and focused at work. As a result, energy levels, alertness and decision-making are increased following morning exercise.
Need for a longer warm up
While there are many benefits to morning workouts, you may need to warm up more thoroughly for morning workouts compared to afternoon or evening workouts. This is because core body temperature is generally lower, heart rate is lower, and your muscles may be tighter in the morning. Engaging in exercise when you are not fully warmed up may cause injury. Therefore, ensure you are fully warmed up before exercising in the morning.
Working out in the afternoon/evening
If you are not an early bird, then it may be more beneficial for you to workout in the afternoon or evening. There are many benefits of working out later in the day, discussed below.
Improved performance
Workouts performed in the afternoon or evening may be associated with a performance boost, particularly for high-intensity exercise. Studies have shown that strength and flexibility levels are highest later in the day.
One study showed that the body’s peak level of muscle force occurs in the afternoon. In addition, a review of studies suggests that strength levels may be between 3% to 20% higher in the afternoon compared to the morning. This suggests that resistance training workouts such as lifting weights may be best performed at this time.
Aerobic exercise abilities may also be improved in the afternoon. One study showed that young men were able to cycle at a standard difficulty for 20% longer in the afternoon compared to the morning.
Lower risk of injury
Body temperature tends to be higher in the afternoon and evening, so your muscles may be already warmed up if you exercise at this time. Warmer muscles are associated with better exercise performance, and lower risk of injury.
Workout feels easier
The perceived exertion of a workout is lowest for afternoon workouts, meaning the workouts feel physically easier at this time. This difference is attributed to circadian rhythm, the body’s biological clock that ebbs and flows over a 24-hour period.
Improved circadian rhythm
Although morning workouts may be best for resetting the biological clock, afternoon workouts may also be beneficial for improving circadian rhythm. Workouts performed between 1 p.m. and 4 p.m. may also help you overcome the afternoon slump and shift the body clock earlier in the same way as a morning workout.
Increased muscle growth
Testosterone is an important hormone for muscle-building in men, and women, and your body may have higher levels of testosterone in the afternoon than morning. This suggests that muscle growth may be best achieved with afternoon exercise, although more research is needed to verify this.
Metabolic benefits
Working out later in the day may help to improve metabolism, which is how the body converts food into energy. One small, 12-week study in pre-diabetic and diabetic men showed that workouts completed in the afternoon had better metabolic effects than those in the morning, including higher fat loss.
Impact on sleep
Performing intense aerobic exercise within one hour of sleep may make it more difficult to fall asleep. However, performing aerobic exercise in the early evening (7 – 8 p.m.) has been shown not to disrupt sleep. In addition, studies have shown that lifting weights in the evening resulted in minimal sleep disturbance. Therefore, working out at night time may not be disruptive to sleep if at least 2 hours is given between the workout time and the
Consistent timing is key
For the average person, the timing of workouts is less important than performing some exercise at all on a regular basis. However, for those that are able to workout regularly, working out at a consistent time may be important, according to research. This is because the timing of our workout can influence our circadian rhythm. Consistently working out at either the morning or evening on a daily basis may be more important than working out at
Exercise and circadian rhythm
The timing of exercise may be particularly important because exercise is a signal for circadian rhythm. Circadian rhythm describes the physical and mental changes that ebb and flow over a 24-hour cycle. Circadian rhythms control a range of bodily processes that occur over daily rhythms such as:
- Hormone levels
- Core body temperature
- Alertness and drowsiness
- Sleep-wake cycle
Circadian rhythms are controlled by the hypothalamus of the brain, which responds to signals in the environment to determine the time of day. These signals for circadian rhythm are known as ‘zeitgebers’, and include the following:
- Light and darkness
- Meal timings
- Sleep timing
- Exercise
Light is the most important signal for circadian rhythm, but the timing of exercise is also important. Your circadian rhythm uses the timing of physical exertion as a signal for determining the time of day, which is why working out at a consistent time may be beneficial.
By adhering to a consistent workout schedule, you are training your body to accurately tell the time so it knows when to sleep and when to be awake.
Circadian rhythm and health
Improving circadian rhythm through a regular 24-hour cycle is important for overall health. This is because a disrupted circadian rhythm is associated with an increased risk of a range of negative health conditions such as:
By improving circadian rhythm, you can improve your overall health by improving sleep quality, and reducing the risk of chronic diseases.
Is the best time to workout personal?
Some research shows that a person’s chronotype may influence the time of day that your optimal performance occurs. However, if your current workout schedule isn’t working, it is possible to change it. Research suggests that your body may adapt to regular exercise at different times of the day by altering your circadian rhythm.
Therefore, any time of day you consistently have free time for physical activity may be the optimal time for you. Consistent timing of your training will help your fitness goals, whilst also improving your circadian rhythm.
The takeaway
The science of when to exercise is still expanding, and there is no clear cut answer. Working out in the early morning can help you build a consistent routine, and sleep better at night, while the early or late afternoon or evening training may allow you to perform at your peak.
However, what’s clear is that working out is important, whenever it is done. Working out for 30 minutes per day can improve your physical and mental health, and reduce your risk of many diseases.
In the end, it’s important to find a realistic workout schedule you can stick to, regardless of the exercise timing. It is also important to keep your workout regime at a consistent time, you may help realign your circadian rhythm.
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