Our bodies’ response to certain types of exercise throughout the day is dictated by the circadian rhythm – the culmination of your ‘biological clocks’. This means that during a 24-hour period, your alertness, core and muscle temperatures, metabolism and hormone levels (such as testosterone and cortisol) will fluctuate. This fluctuation is affected by daylight, eating habits, genes and exercise.
Your body will have a better response to different types of training at certain times during the day. To lift under fatigue you need to be well fuelled and alert, and you don’t need to lift particularly heavy weights, so muscle temperature and testosterone levels can be lower. For example, if you are looking to increase muscle size a training day could be:
To lift heavy you need to be well fuelled, alert, have a high muscle temperature and have higher testosterone going into the session in order to increase weights lifted. So, if you are looking to increase muscle strength, it is best to:
If you want to target fat loss from cardio, the ideal sessions are:
If you are targeting general fitness from cardio, the ideal sessions are:
Intense or light cardio can be done at any time of day, as muscle temperature and hormone levels do not factor too much. It is important to bear in mind though that intense cardio requires higher fuel stores.
If you have to lift early in the morning, there are several options that will help you perform better.
If you need to train late (which isn’t ideal as it will disrupt your sleep pattern):
If you try to do fasted cardio later in the day:
One thing to consider is that everyone is different; some people are early birds, and some are night-owls – see Elise and George’s blog post here to find out more about when the optimum workout time is depending on your circadian rhythm.
In order to change from one rhythm to another you need to adjust your eating times, workout times and waking/sleeping times. For regular training, it is important to keep a consistent body clock, as infrequent wake-up times can lead to unwanted weight-gain and illness.
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