Exercising at any time of the day is beneficial for your health. If, however, you're looking to achieve optimum results in terms of weight loss, the timing of your workout is crucial. To identify the best time of day to perform your workout, it's essential to understand how, and more specifically when, the body burns calories; as well as to be aware of the risks involved in working out at particular hours and how to avoid them.
Fitness experts propose that midday exercise is ideal for rigorous training, as your body's muscles are warm and flexible and your energy levels are at their highest. However, basic physiological principles suggest that the morning may be the best time to exercise if your goal is to lose weight. Not only will morning exercise improve your body's ability to burn calories more efficiently, it will also improve its ability to shed those extra pounds.
To lose weight you need to burn more calories than you consume, as well as increase your basal metabolic rate--the rate at which your body burns calories while resting--through regular exercise. While you exercise, your metabolic rate peaks, then gradually returns to its basal rate over several hours, finally reaching its lowest point during sleep. Furthermore, while you sleep your body continues to draw energy from its glycogen stores to sustain basic bodily functions.
By exercising in the morning, your body will turn more readily to its fat stores for energy--or ATP production--as its glycogen stores have been depleted overnight. Additionally, because exercise boosts your metabolic rate in the short term as well as your basal metabolic rate in the long term, the rate at which you burn calories throughout the day will be further enhanced. It's also important to note that since your metabolic rate drops toward the end of the day and hits at an all time low during sleep, exercising in the evening, by contrast, will be a wasted opportunity to prolong your heightened metabolic rate, which could otherwise be sustained throughout the course of the day.
Unfortunately, although it's an ideal time to maximize weight loss, morning exercise does pose its risks. For the first couple of hours after waking your energy levels are low, as most of the nutrients you ingested the day before have been utilized during sleep, and your muscles are generally cold and stiff. Both of these factors increase your chances of fatigue and injury. Additionally, if you exercise before breakfast, your body's muscle tissue, in addition to your fat, may be burned as an energy source.
To avoid injury, it's vital that you warm up and stretch your muscles before exercise. Furthermore, say experts at the Australian Institute of Sport,“If you train early in the morning, you should opt for a light snack about an hour before exercise. For example, some fruit or a cereal bar on the way to training along with some fluid such as a glass of milk or juice.”