Welcome back to the club. Today's edition explores:
Deep Dive: How late is too late for a hard workout
Pillar Spotlight: How much coffee should you drink
Video of the Week: Five simple habits for a healthier gut
DEEP DIVE
How Late Is Too Late To Work Out?
Is exercising in the evening bad for your sleep? The old advice says yes, but a huge study using wearable data gives a more precise answer.
Researchers at Monash University in Australia looked at 14,689 people who wore a WHOOP fitness tracker for a year, adding up to more than 4 million nights of sleep. Most were men, with an average age of about 38.
The tracker scored each workout's strain, from light to maximal, based on time spent in different heart rate zones. It also recorded when people fell asleep, how long they slept, and their heart rate and heart rate variability (HRV) overnight. HRV is a sign of how well your body is recovering, and higher is generally better.
Timing mattered most. Workouts that ended at least four hours before someone's usual bedtime were not linked to falling asleep later or sleeping less, however hard they were.
Closer to bed, though, harder workouts took a toll. Compared with a light workout, a maximal one ending two hours before usual bedtime was linked to falling asleep 36 minutes later and sleeping 22.2 minutes less. Overnight resting heart rate was 3.9 beats per minute higher, and HRV was 14.1 percent lower.
Working out after your usual bedtime was worse still. A maximal workout ending two hours after usual bedtime was linked to falling asleep 80 minutes later and sleeping 42.6 minutes less than a light one.
The study does have limits. It was observational, so it shows links, not cause and effect. The tracker could not tell when people first tried to sleep, and its strain score may underrate strength training. Moreover, most participants were men who exercise a lot. And two of the authors
Still, the message is clear. Evening exercise is fine, as long as the hardest sessions finish a few hours before bed.
The Protocol
Finish Hard Sessions Early: Workouts ending at least four hours before your usual bedtime were not linked to later or shorter sleep, however hard they were.
Keep Late Sessions Light: If the evening is your only window, choose an easy session like a walk, a gentle cycle or some stretching. Light workouts had much smaller links to sleep.
Plan Around Your Usual Bedtime: The study measured timing against each person's usual sleep time, not the clock. If you normally fall asleep at 11pm, aim to finish a hard session by about 7pm.
Move It, Don't Drop It: The researchers stress that exercise is essential for health. The aim is to shift the hardest sessions earlier, not to skip them.
PILLAR SPOTLIGHT · NUTRITION & CELLULAR HEALTH
Your Daily Coffee Might Be Healthier Than You Think
Good news for coffee lovers! Your daily cup might be doing more good than harm.
A major review published in the BMJ looked at more than 200 analyses of studies on coffee and health.
The sweet spot seemed to be three to four cups a day. Compared with people who didn't drink coffee, those who drank this amount had a 17% lower risk of death during the studies and a 19% lower risk of dying from cardiovascular disease. Drinking more coffee was also linked to an 18% lower risk of cancer.
Of course, most of these studies found links rather than proving that coffee itself caused the benefits. The review also noted some risks during pregnancy and a possible link to fractures in women.
But for most people, the findings are reassuring. If you enjoy your daily coffee, there's good reason to keep enjoying it. Just try to have it earlier in the day if it affects your sleep.
VIDEO OF THE WEEK
Five Habits For A Healthier Gut
Your gut bacteria affect far more than digestion, from your immune system to your appetite. Professor Tim Spector shares the five habits he lives by for a healthy gut, from eating more plants to trying fermented foods. Simple, practical advice you can start at your next meal.
That's it for this week.
Move your hardest workouts earlier in the day, and keep late sessions light. Enjoy your coffee, ideally before the afternoon. And try one of Tim Spector's gut tips this week, like adding an extra plant to your plate. Small steps, and all of them easy to start.
Take care of yourself,
The Vitality Club
THE SUMMARY
Key takeaways
A 2025 study in Nature Communications analysed 4,084,354 nights of data from 14,689 WHOOP users.
A maximal rather than light workout ending 2 hours before usual bedtime was linked to falling asleep 36 minutes later and sleeping 22.2 minutes less.
After those late, hard workouts, overnight resting heart rate was 3.9 beats per minute higher and HRV was 14.1 percent lower.
Workouts ending at least 4 hours before bedtime were not linked to later or shorter sleep, whatever their intensity. The study was observational, and two authors work for WHOOP.
A BMJ umbrella review linked three to four cups of coffee a day with a 17 percent lower risk of death compared with none.
Sources
Leota J, et al. (2025). Dose-response relationship between evening exercise and sleep. Nature Communications.
Poole R, et al. (2017). Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ.
About the authors
The Vitality Club is written by PhD researchers at Durham University, Marcus W, Camila G and Todd B, who turn new peer-reviewed health and longevity research into practical takeaways. This article is for education only and is not medical advice; talk to a qualified healthcare professional before changing your diet, exercise, supplements or medication.