Exercise and Sleep: Timing Workouts for Better Sleep and Longevity
Originally sent to subscribers on 1 June 2025
The Million Hour Memo
Here's a question I've been asked this week:
“I like exercising in the evening on my way home from work but could this be affecting my sleep?”
Let's dive in...
DATA
Where insight becomes impact
What I’ve been looking at this week…
Here's what caught my attention:
“Effects of Exercise Training on Sleep Quality: A Systematic Review and Meta-Analysis” (Chennaoui et al., 2021, DOI: 10.1016/j.smrv.2021.101543). This reviewed 22 studies with over 1,100 people.
The conclusion? Exercise is one of the most underused sleep tools available.
Aerobic training like walking, running, cycling improves how long and how deeply you sleep.
Resistance training reduces sleep latency—the time it takes to fall asleep.
Mind-body movement like yoga or tai chi improves how rested you feel—even before your metrics shift.
The old myth about avoiding evening workouts because they disrupt sleep? Disproven.
The mechanisms? Lower cortisol, improved serotonin–melatonin conversion, enhanced thermoregulation, and stronger circadian synchronisation. Your body can sleep after exercise—it just needs the right kind of exercise.
DEVICES
Track it to hack it.
What I’ve been monitoring this week…
With this study in mind, I’ve been paying attention to how different workouts affect my own sleep metrics. Here’s what’s been interesting:
Stretching: This helps me feel better the next morning, even though my REM sleep doesn’t increase much.
Strength training: This increases my deep sleep by 18–22 minutes.
Evening cardio: This only improves my sleep if I finish at least 90 minutes before bed and slow down my breathing before I sleep with 6‑60 breathing, which brings my heart rate down.
Here’s what I use:
Oura Ring: Tracks sleep efficiency, architecture, latency, HRV.
Workout tagging: To compare data by training type.
FlexiBuddy by my desk: Better mobility during the day → better parasympathetic tone at night.
One of my favourite moments with clients? When their data confirms what their body’s signalling. That’s why I love showing you how to blend innate intuition with transformative technology—so you learn to tune in to yourself.
DECISIONS
From knowing to doing.
What this means for YOU…
Let’s get specific—because general advice doesn’t change your biology. Here’s what to apply and what I do in clinic:
If you fall asleep easily but wake up at 3 or 4 am
That’s a possible cortisol surge. Your autonomic nervous system is likely to be hypervigilant. Add mid‑morning strength work and pair it with 6‑60 breathing at night to control and calm your HPA axis: slow your breathing rate down to 6 breaths a minute for 60 seconds to lower nighttime cortisol. Test your cortisol levels to be more specific.
If you wake up feeling unrefreshed after 7+ hours sleep
Your sleep cycles may be shallow. You may be moving too little during the day or too intensely too late. Add Zone 2 cardio in the afternoon and use blue light in the morning to reinforce your circadian rhythm. Do the 1‑10: go outside into the morning light for 1 minute and take 10 seconds to think about the purpose of your day. Eyes open, purpose primed.
If you’re struggling with stress and sleep together
Your body might need stillness, not sweat. Swap one HIIT session for yin yoga or tai chi. Measure your HRV change after one week—you’ll see the difference. Remember: you don’t always need more movement. You need the right movement—at the right time, in the right amount. And you don’t need to guess—your data will guide you.
Case in point
One of my private clients, an early‑stage VC founder, was stuck in a loop of 4 am wakeups despite magnesium, meditation, and blackout curtains. His metrics:
Low deep sleep (<40 minutes/night)
No resistance training
High resting heart rate overnight
What we changed:
Added 25 minutes of resistance training, 3×/week before 2 pm
Introduced glycine and 6‑60 breathwork 90 minutes before bed
In 3 weeks:
Deep sleep doubled
No more 4 am waking
HRV improved by 9 points
Productivity up, cortisol curve corrected
This is the Million Hour Method in motion. What does your body need? Not more effort—more precision.
DIARY
Where you’ll find me…
Last week:
In just 48 hours I’d been in the ITV studios in London, on set with Good Morning Britain, zipped over to a podcast studio in Cardiff to share business biohacks with property investors and then into the heart of Pembrokeshire for The Big Retreat Festival. I ran a longevity cooking session in the Chef’s Kitchen, hosted by the ever‑fun and flairy Kwoklyn Wan. I made my signature Longevity Bowl—with magnesium‑rich seeds, adaptogenic herbs, and a rainbow of phytonutrients designed to support sleep and cellular rejuvenation. What a fantastic few days!
This week:
I’m in Rimini, Italy with my boys—who are Hyrox’ing their hearts out. Fitness fuelling the family—nothing better. Then it's straight back to London to speak at The Foundxrs Club, diving into longevity strategies for elite entrepreneurs.
Next week:
Off to Marbella for The Betterman Retreat where I'll be running a live Biohacking Circuit—can't wait for that. Then back to London speaking at Wellnergy which I am so looking forward to. And I have tickets for The Wellnergy Festival for you! Book here and use code return20 for 20% off. It would be lovely to see you there, so do come and say hello!
DISTINCTION
A thought to pause on…
“Sleep is where the body trains for tomorrow's demands.”
So here’s the question I leave you with this week: How are you exercising during the day to earn the sleep you want at night?
Wishing you a wonderful week ahead!
Dr Alka