Some women swear by a 6am jog to set them up for the day. Others can’t imagine breaking into a sweat before lunch However, as well as being a personal preference, the time of day you choose to exercise can also affect your health and sporting performance. So, what is the best time of day to run?
Your body has its own natural timing device, or body clock, situated in a tiny cluster of nerve cells in the brain. This takes its cue from changes in daylight and controls many physiological processes – such as body temperature, blood pressure and hormone secretion – regulating them on a 24-hour cycle. These in turn, can affect how well you can run.
An early morning run can leave you alert and ready to face the day at your best. ‘If you exercise outside in the early morning natural light it can help wake you up and release feel good hormones,’ says physiotherapist Sammy Margo.
But if you are slower to get going it can leave you drained and exhausted and it’s best avoided. ‘People are like engines: petrol where they fire quickly in the morning and diesel where they take time to get going.’ says Sammy.
Whatever your preference, launching your resting body straight into intense physical activity can be a brutal shock that risks injury. Your core body temperature is lower and your body is tight because you have been resting in one position for many hours. ‘All your joints, ligaments, muscles are tendons are not as warmed up as will be later on so be careful – we see lots of injuries that happen at this time in the morning, especially back injuries,’ says Sammy Margo.
The earlier you exercise, the longer you need to spend warming up. So, for example, if you normally jog slowly for six minutes before you start to run faster for 40 minutes in an afternoon session, increase this warm up to ten-12 minutes first thing.
Exercise in the early morning may also feel more difficult because it is harder to get the amount of oxygen we need into the body than it is later in the day because airways are more constricted after a night’s sleep. Also there is less adrenaline circulating in the bloodstream that can make exercise feel more effort.
This is a good time to find co-workers to exercise with. It can also help keep you alert for the afternoon, because our body has a natural lull just after lunch, called the post-prandial dip. But take care to eat after exercise or you could find you need the toilet halfway round the course or feel heavy and nauseous.
According to Professor Jim Waterhouse, an expert in the human body clock at Liverpool’s John Moores University, for more severe exercise the best part of the day is late afternoon, early evening – especially if you want to set a personal best. ‘The best performances and the breaking of world records occur at this time,’ he says. This is because body temperature, cardiovascular and respiratory rhythms and adrenaline secretion all peak at this time. We also perceive exercise to be easier at this time of the day, because our lungs are more efficient at taking in oxygen and our muscles are already warm and active. However, because our bodies are at their hottest, marathon runs and training may be better earlier to avoid overheating.
Sometimes, the day has been so busy there is no option but to exercise late. But, there’s also a risk of poor sleep or even insomnia. ‘Exercise raises your heart rate and body temperature and stimulates your mind – not particularly conducive to sleeping,’ says Sammy Margo. An advantage, however, is that you are less susceptible to bacteria and viruses and your immune system is at its highest because rates of the hormone cortisol are falling. Leave plenty of time to digest your evening meal and if you must exercise late, allow for a longer cool down than you’d expect earlier in the day.