Why small sleep, diet, and exercise changes work better together

That’s why, instead of aiming to perfect one big routine, behavioural science recommends focusing on making one change at a time. These don’t need to be huge, and mastering one small change can actually make the next one easier.

A new study has taken a different approach to most other research in that it’s examined the effects on cardiovascular health of sleep, exercise, and diet together rather than separately.

“Sleep, activity, and nutrition are almost always studied in isolation, despite being deeply interconnected in real life,” explains Dr Vishal Shah, Thriva's Chief Medical Officer.

“Poor sleep affects appetite hormones and food choices. Physical activity influences sleep quality. Diet affects the energy you have to move. They're part of one system, and this study treats them that way.”

Let’s take a look at what the researchers found.

What was the combined impact of sleep, exercise, and diet?

The study, published in the European Journal of Preventive Cardiology, aimed to see how sleep, physical activity, and nutrition together impacted the risk of heart attack, heart failure, and stroke.

The authors looked at data from 53,242 people from the UK Biobank over the course of 8 years. They estimated hours of sleep and minutes of vigorous physical activity per day with data from wearable devices, and they used questionnaires to get an understanding of their diets.

Each participant received three scores to reflect their sleep, physical activity, and nutrition (SPAN). Combined, these three lifestyle components added up to give each participant a SPAN score.

After analysing the data, the researchers found that targeting all three lifestyle behaviours could lead to significant cardiovascular benefits in the long-term.

Having the ideal combination of lifestyle behaviours (giving the highest SPAN score) was associated with a 57% lower risk of cardiovascular concerns, in comparison with having combinations giving the lowest SPAN scores.

This ideal combo included 8–9.5 hours of sleep a night and 40–105 minutes of vigorous exercise a day.

“It's a substantial reduction,” says Dr Shah. “The group with the best combination of sleep, activity, and diet had roughly half the rate of heart attacks, strokes, and heart failure compared with the group with the worst, over 8 years of follow-up across 53,000 people.”

But more modest improvements in these lifestyle behaviours also appeared to produce results. The authors reported that getting an extra 10 minutes of sleep, 5 minutes of exercise, and a small amount of extra vegetables each day was associated with a 10% lower risk of heart attack, heart failure, and stroke.

While 10% might not sound like a big change, it could actually translate to a large difference.

“It matters more for someone starting from a poor baseline, which is where this study measured it,” explains Dr Shah. “Cardiovascular disease is the leading cause of death globally, so at a population level, even a 10% shift translates to a very large number of heart attacks, strokes, and heart failure cases prevented.”

Why do healthy habits work better together?

The fact that the study combined different approaches (rather than studying them separately) is part of what makes it exciting.

“We've known for a long time that sleep, physical activity, and diet each matter for cardiovascular health,” says Dr Shah. “What's most valuable about this study isn't any single finding, it's the fact that these three behaviours were examined together. That sounds obvious, but it's genuinely unusual.”

There are lots of studies that examine these lifestyle behaviours on their own. But the effects of each on our body are interwoven so closely that by only looking at one behaviour, you’d be missing a big part of the picture, and potentially limiting what changes you could make.

Sleep, physical activity, and nutrition “share the same biological pathways to cardiovascular disease — inflammation, blood pressure, blood sugar control, endothelial dysfunction,” says Dr Shah.

“Treating them as separate problems leads to separate recommendations that don't reflect how people actually live. This study makes a strong case for looking at them as a package.”

We can see this point when comparing the effects of changing one of the behaviours versus making improvements with all three. Here, the effort needed to reduce your risk of cardiovascular problems appears much greater if you only focus on one area.

“To achieve a 10% lower cardiovascular risk through sleep alone, you'd need around 30 extra minutes per night,” says Dr Shah. “But combine just 10 minutes of additional sleep with modest improvements in activity and diet, and you get the same result.

What limitations did the study have?

The study had some limitations that are important to be aware of.

“It is an observational study, so it reflects associations rather than guaranteed outcomes,” acknowledges Dr Shah, “but the size of the reduction is hard to ignore.”

One of the tricky things with assessing the combined effects of three different behaviours is that the ways to measure them can differ a lot. Here, the researchers relied on diet self-reporting, which can be susceptible to inaccuracy.

Finally, the researchers reported only observing a “weak synergistic relationship” between the behaviours, suggesting that we shouldn’t interpret their results as showing the three behaviours as interacting with each other. But as Dr Shah says, the scale of the risk reduction is a very compelling one.

Perhaps the most important takeaway here is not to get too drawn on the idea that it’s vital to optimise all three of these behaviours.

Sure, getting the optimum scores for sleep, exercise, and diet was associated with the biggest risk reductions. But getting to that point can be very hard. And if you’re looking to make changes to improve your health, we can see from this study that small incremental differences are associated with respectable benefits.

What small changes to sleep, exercise, and diet actually look like

The study found that relatively small improvements in sleep, physical activity, and nutrition together were associated with a reduced risk of cardiovascular problems. So what did these improvements look like in real life?

• Sleep: An extra 10 minutes a night
• Physical activity: An extra 5 minutes of vigorous exercise a day
• Nutrition: Approximately an extra ¼ cup (a small handful) of vegetables a day

To get that extra sleep, you could try sitting down to dinner a bit earlier or getting ready for bed a bit sooner. If you like to watch TV to unwind, you could aim to watch a programme that has half-hour episodes rather than 45-minute ones.

Learn more about how to get better sleep with Dr Sophie Bostock.

You could squeeze in some extra minutes of exercise throughout your day with exercise snacks. Try to add some in during little breaks throughout the day: climb up and down some stairs while waiting for the kettle to boil, or try some star jumps at the start of your lunch break.

ABBA’s ‘Gimme! Gimme! Gimme!’ is just under 5 minutes long, so you could also whack that on and dance around the kitchen once a day. This is highly recommended.

For a simple way to add more plant foods to your diet, why not turn to tins? Tinned lentils, carrots, and peas are quick and easy to add to most meals.

Hopefully, these suggestions show that the kind of small changes the study calls out are ones that don’t require you to radically revamp your existing routine.

And due to the way that sleep, exercise, and diet all impact each other, hopefully you’ll find that the improvements are a rising tide that lifts all boats, making it easier to make further changes in the future if you want or need to.

What's next

A new study suggests that improvements to sleep, physical activity, and nutrition altogether are associated with a reduced risk of heart attacks, heart failure, and stroke. Relatively small simultaneous improvements across the three behaviours were associated with similar benefits to those associated with larger improvements in a single behaviour.

“Too often, health messaging sets targets that feel out of reach: 150 minutes of exercise per week, overhauling your diet, optimising your sleep. This study suggests meaningful benefits may come from much smaller changes, provided they're made across multiple behaviours at once,” says Dr Shah.

“It doesn't matter where you start, as long as you start somewhere.”