Week 9: Why sleep is more important for performance and recovery than you think

Sleep isn’t just a nice-to-have, it’s a necessity.

Quality rest helps your body to recover, boosts your energy and sharpens your focus for training.

Whether you’re gearing up for your first 10K or chasing a new PB at the Vitality 10,000, sleep could be the missing piece in your performance puzzle.

Research shows that not getting enough sleep can reduce endurance, slow down recovery and even increase your risk of injury.

One study published in Sleep Health found that athletes who slept fewer than eight hours a night were 1.7 times more likely to get injured than those who slept more.

Another from Stanford University revealed that basketball players who extended their sleep improved both their sprint times and shooting accuracy.

“Sleep was always a non-negotiable part of my training”

– Jessica Ennis-Hill, Vitality Ambassador

So, if you’re putting in the miles but skipping the rest, your gains might be slipping away overnight.

To help you get the most out of your training, Jonny Kibble, Vitality’s Head of Physical Activity and Exercise, explains why sleep matters more than you think – and how to get more of it.

Why syncing your sleep matters

It all comes down to your circadian rhythm. This is your internal body clock that regulates sleep and wake cycles.

Kibble explains: “Syncing your sleep schedule and routine to natural cues like light and temperature helps improve both sleep quality and quantity.”

To keep it consistent, he recommends:

• Going to bed and waking up at the same time every day
• Getting at least 30 minutes of natural sunlight during the day
• Avoiding screens and blue light in the evening
• Reducing caffeine intake, especially after midday

Melatonin, the hormone that regulates our sleep-wake cycle, “is directly impacted by light exposure,” says Kibble.

So, being mindful of your environment throughout the day can make a big difference.

How sleep supports recovery and performance

Sleep isn’t just about feeling rested, it’s when your body gets to work repairing itself.

During deep sleep, human growth hormone is released to help muscles recover and rebuild.

REM sleep, the ‘dream state’ of sleep, supports cognitive function and emotional regulation, which are both essential for motivation and focus during training.

Vitality Ambassador, Jessica Ennis-Hill agrees: “Sleep was always a non-negotiable part of my training.

“I knew that if I didn’t prioritise it, I wouldn’t perform at my best – physically or mentally.”

Five tips for better sleep and improved training

1. Set the scene

Your body responds to cues like light and temperature. Create a sleep-friendly space by using blackout curtains, keeping your bedroom cool (around 16–18°C), switching off screens at least an hour before bed and opting for warm-toned lighting or candles in the evening.

2. Time your meals and caffeine

Digestion can disrupt sleep, so try to avoid big meals within three hours of bedtime. And keep caffeine to earlier in the day. It affects adenosine, a hormone that builds sleep pressure, so having it late can make it harder to nod off.

3. Move your body – but not too late

Exercise helps improve sleep quality, but intense workouts close to bedtime can raise your body’s temperature, making it harder to wind down. Gentle evening walks are fine, but save the high-intensity stuff for earlier in the day.

4. Nap smart

If you’re not getting enough sleep at night, a short nap can help. Aim for around 20 minutes, which is just enough to feel refreshed without falling into deep sleep. And try to nap before 3pm so it doesn’t interfere with your nighttime rest.

5. Stick to a routine

Consistency is key. Going to bed and waking up at the same time every day (even on weekends) helps regulate your internal clock and improves sleep quality over time.

Sleep isn’t just a passive part of your training plan, it’s an active contributor to your success.

Prioritising rest means you will recover faster, train harder and feel better.

As Ennis-Hill puts it: “Sleep is the foundation of performance. It's time for the body to recover, without it we can really struggle.”

So, as you head into the final weeks of your Vitality 10,000 training, don’t just focus on the miles, focus on the hours between them, too.