The pros and cons of exercising after 8pm

“Insulin sensitivity is down to an interaction between the hormones. Cortisol and insulin are almost inverse; cortisol breaks down while insulin builds,” explains NHS GP and personal trainer Dr Amos Ogunkoya. “We know that cortisol levels are higher in the morning and cortisol tends to hold onto fat. That means exercising later might allow you to actually do a better workout – especially as most of us have time limitations in the morning but more time in the evening.”

We know exercise has stress-relieving properties and further studies link evening exercise to falling asleep faster and spending more time in deep sleep. So, knowing how good it is for me, could I, a sworn morning person – who frequently goes to sleep in full daylight and to the sound of young children playing outside – switch my routine around? Could I become a fitness owl?

Monday evening yoga class

Not wanting to throw myself into anything too brutal straight off the circadian bat, I opted for a Monday evening yoga class. To get there involved a short bike ride in the setting sun. Which was picturesque until an enormous brown rat ran across my path. That’s one problem with being out and about in the evening – so are the rodents. 

Somehow, the slowness of yoga – all that breathing and stretching and listening to your body – can feel frustrating to me in the morning. But after a full day of work, childcare, unpaid domestic labour and the news, I relished the idea.  As a beginner, I found my muscles shaking like a Polaroid picture after even just a few seconds of downward facing dog.

Verdict

Yoga’s seriously good for you. One 2016 study by the Rockefeller University in New York showed that participants doing yoga three times a week significantly improved bone mineral density in their spine, hips and thigh bones. The slow breathing has been shown to have a calming effect on our nervous system and reduce our stress levels too – both conducive to getting eight hours of sleep, which also happens to be linked to good heart health. 

Tuesday evening run

With my metabolic processes in mind, I had an extremely early dinner on Tuesday with my son to be ready for a run after his bedtime. It felt completely bizarre, bordering on scandalous to be pulling on a pair of Lycra shorts at 8pm.

But, honestly, how else are parents to small children supposed to capitalise on all this evening insulin regulation? I may have provocatively suggested to my partner that “vigorous physical activity in the evening is widely acknowledged as a therapeutic strategy for improving cardiometabolic risk factors,” but I’m not sure it was quite the seductive line I’d hoped. So, I was stuck with running.

The problem with something as high adrenaline as a jog down the towpath, at night, is that by the time I got home a little over an hour later, sweaty and with my pupils dilated, I was in no fit state to fall asleep. 

Verdict

Despite a hot shower and cup of chamomile tea, I lay in bed for at least an hour and a half, completely unable to switch off. Indeed, studies show that in order for evening exercise to improve sleep it needs to be moderate intensity, not vigorous and end at least an hour before bedtime. Lesson learned.  

Slower exercise definitely seems more conducive to good sleep but I don’t want to give up my running. Thankfully, Dr Ogunkoya reassures me that doing something is always better than nothing – whatever the time. “The biggest contributor to diabetes, cardiovascular disease and cancer is a sedentary lifestyle,” says Dr Ogunkoya. “So, if you find cardiovascular exercise in the morning easy then go with that. And maybe do weights in the evening.”