the case for… TIME
To reap the rewards of everything from better heart health to stronger bones, the NHS has given you a pretty simple target to shoot for: 150 minutes of moderate activity per week or 75 minutes of vigorous activity. For context, that’s five 30-minute moderate workouts per week, or five 15-minute vigorous sessions – mix and match as you will. The former is really anything that raises your heart rate a bit, and encompasses everything from cleaning to a brisk walk (you should still be able to talk, but not sing, according to the NHS). Vigorous activity is (you guessed it) more intense. Think: a run, skipping or one of the HIIT workouts you’ll find on the WH Youtube channel.
Studies confirm that there’s something in those manageable values. One, published in JAMA Internal Medicine, which analysed the exercise habits of 660,000 people, found those who exercised one to two times the recommended weekly amount had a 31% lower mortality risk than those who didn’t exercise at all; those doing two to three times that much exercise saw a 37% lower risk, and those doing five times the amount had a 39% lower risk. Time spent sweating also counts in matters of mental health; a 2016 study* found that 20 minutes of exercise could help boost brain chemicals glutamate and GABA – two neurotransmitters vital for memory and mood.
If you’re new to exercise and looking to increase strength and cardiovascular fitness, lowerintensity, time-based workouts are a great place to start, says Dr Rebecca Robinson, consultant in sports and exercise medicine at the Centre for Health and Human Performance and WH Fit Squad member. ‘Steadily increasing the time you spend exercising will get the cells within the muscles – the mitochondria – to develop,’ she says. ‘Greater mitochondria density is important in endurance, but also metabolically.’ Why? Mitochondria are the cells that generate most of the chemical energy needed to power cells’ biochemical reactions – in other words, they convert fuel from the food you eat into energy your body can use to move.
‘You’ll often hear athletes, particularly runners, talking about building a “base” – time spent working on mileage before they’re ready to push the intensity,’ adds
Time spent sweating counts for mental health
Dr Robinson. A prime example is Couch to 5k – where the goal is time spent on the move, rather than bursts of all-out effort. The same applies to most forms of exercise, she adds, whether you’re a runner, a cyclist or lifting in the gym. ‘Building a base means conditioning that system, including the muscles, ligaments and tendons, which is essential in preventing injury. Because, while quick, high-intensity blasts can be good, is your body ready for that?’