Researchers find the perfect daily balance of sitting, standing, and sleeping to protect heart health. Photo / 123RF
For the good of our physical and mental health, most of us should be exercising and sleeping more and spending less time slumped in our chairs. But the data shows we’re not.
Our sedentary lifestyles mean we clock up too many hours sedentary (aroundnine hours a day, once you factor in commuting, working at desks and sitting on the sofa) and too little time moving, to the detriment of our bodies.
But exercise researchers in Australia believe they have uncovered how to spur us to get out of our seats – by pinpointing exactly how long we should spend sitting, standing, exercising and sleeping every day to protect our hearts.
Previously, no one had put a cap on how much of our day we should spend sitting, though the UK’s chief medical officers have warned that prolonged seating is risky.
Now, researchers from the Baker Heart and Diabetes Institute in Melbourne claim to have found the sweet spot.
They examined data on around 2,400 people in the Netherlands, aged 40 to 75, who wore activity trackers for a week and had a health check-up. The team then fed this data into an algorithm that calculated the “optimal” duration people should dedicate to different activities for the lowest risk of heart disease and type 2 diabetes.
Results show six hours and 10 minutes is the “Goldilocks” for sitting – much less than the nine-hour average clocked up by participants and people in the UK.
“This identifies a target for people to strive for, for heart and diabetes health,” says Professor David Dunstan, head of physical activity at the institute and study author.
However, those who spend less than six hours and 10 minutes of their day sitting should “keep it up”, he says. “The fundamental principle here is that any time spent sitting displaces time spent in physical activity and that more movement equals better health.”
Too much sitting has been linked to being overweight or obese, developing type 2 diabetes, suffering from cardiovascular disease and dying early.
“Spending prolonged periods of time sitting (in large chunks) is the most harmful pattern, while more interrupted sitting (breaking up sitting with activity regularly) is more ideal for heart and diabetes health,” Dunstan says.
Standing
Recommended: Five hours 10 minutes
“In our study, the average time spent standing was already four hours and 20 minutes,” says Dunstan. But his team found that an additional 50 minutes (five hours and 10 minutes, in total) was linked with the lowest risk of heart problems and type 2 diabetes.
“It comes back to whittling away time spent sitting with either some additional standing,” he says. “If standing displaces time spent sitting, it can help to offset some of the negative health effects.”
Compared to sitting, standing increases blood flow throughout the body and blood flow to the brain and contributes to improved regulation of blood sugar, blood fats and inflammation, Dunstan notes.
But you don’t need to spend hours standing at a time, as this can trigger a separate host of problems, including tired muscles, swollen legs and back pain. Research suggests limiting standing to 40 minutes at a time can avoid these effects.
Sleeping
Recommended: Eight hours and 20 minutes
“Sleep is an essential ‘restorative’ process for the body and poor sleep can have multiple consequences for heart health – including indirectly affecting choices about what and when we eat and our physical activity patterns,” says Dunstan.
His paper suggests that eight hours and 20 minutes of sleep per night is ideal for heart health – in line with long-standing guidance that adults need around eight hours. However, most in the UK report falling short and clocking up just seven hours per night.
Being well rested has knock-on effects beyond how tired we are. Research suggests we eat more on days when we’re sleep-deprived (adding up to nearly 400 extra calories), leaving us at risk of weight gain, which can risk heart health and increase the chance of developing type 2 diabetes.
Additionally, when we sleep, our breathing and heart rate slow and our blood pressure drops by around a fifth. This places less stress on the heart compared to when we’re awake.
Light activity (housework, gardening, walking)
Recommended: Two hours, 10 minutes
Squeezing in more light-intensity activity can eat into the time we spend sitting and improves blood pressure, blood sugar and blood flow to the brain, explains Dunstan. Examples include housework, cooking, gardening and walking.
“Just like high blood pressure, high cholesterol or smoking, being inactive for long periods can increase the risk of heart and circulatory disease,” says Sindy Jodar, senior cardiac nurse at the British Heart Foundation.
“Becoming more physically active can help to keep your weight under control, lower your blood pressure and cholesterol, and reduce your risk of developing diabetes.”
Dunstan recommends adding more movement to your day by standing up and walking around during TV advert breaks, staying on your feet during phone calls and taking the stairs instead of lifts or escalators.
Moderate or vigorous activity (walking up stairs, running, swimming)
Recommended: Two hours, 10 minutes per week
All adults should be doing at least 150 minutes of moderate exercise (brisk walking, cycling, doubles tennis) or 75 minutes of vigorous exercise (running, swimming, walking up stairs) per week, under official UK guidance.
But Dunstan and his colleagues say people should really aim for around that much every day (130 minutes). Keeping physically active reduces the risk of a host of heart problems, including heart disease, heart attacks and strokes, as well as Type 2 diabetes and cancer.
“As we become more physically active, our heart rate, breathing rate and blood pressure will increase to ensure that our muscles are getting enough oxygen to keep up with demand,” says Jodar.
“When done regularly, moderate and vigorous intensity physical activity strengthens our heart muscle. This improves how well the heart can pump blood around the body.”
She recommends starting small and increasing the time you dedicate to moderate exercise that you already do, like walking. “Once you’re feeling more comfortable, you could also try activities like cycling, water aerobics or brisk walking,” Jodar recommends.
Alongside this, she suggests adding short 10 minute bursts of vigorous exercise. “It’s never too late to get active, regardless of how little you have exercised in the past,” she says.