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Some health benchmarks are outdated. If you want to stay fit, disease-free and mentally sharp for life, then consider these new science-proven trackers of wellbeing
Drink eight glasses of water
Urinate five times
If you were to wring all the water from your brain, it’d lose about three-quarters of its weight. In fact, every cell in your body relies on water for survival. Studies suggest that dehydration hampers your endurance, motivation and mental sharpness. Problem is, the old eight-glasses-a-day advice is too broad, says Dr Jesse Mills, director of the UCLA Men’s Clinic. A 60-kilogram man, for instance, needs far less water than a 100kg CrossFit fanatic. So stop counting trips to the water cooler. If you urinate four or five times a day – say, one litre total – then you’re hydrated. If not? Drink.
A serious athlete can sweat as much as 10 per cent of his body weight during a workout, according to a study in the journal Nutrition Reviews. So plan to replenish after a hard sweat session: weigh yourself before and after you exercise, and then drink 500 millilitres – slowly – for every 500 grams you lost.
A BMI under 25
A waist-to-hip ratio under 0.9
In a University of Texas study, up to 10 per cent of men with physically active jobs were wrongly classified as obese using BMI criteria. BMI estimates fail to distinguish between muscle and fat; in fact, after assessing more than 15,000 adults, Mayo Clinic researchers found that men with high waist-to-hip ratios were twice as likely to die over the 14-year study period as men with high BMIs. To calculate your ratio, measure your waist at your belly button and your hips at their widest point. Divide the first number by the second; 0.9 or above means you have too much visceral fat, the kind that promotes type 2 diabetes and high blood pressure.
To flatten your belly, crank up the intensity. In a University of NSW study, men who did 20-minute interval sessions three times a week on an exercise bike – alternating between eight-second sprints and 12-second rests – reduced their belly size (and visceral fat) more than those cycling at a moderate pace.
Low intake of saturated fat
Four hours a day standing at work
Saturated fat took a big hit a few decades back, when research linked it to heart disease. That science has since been debunked, but the perception lingers. So let’s be clear: there is no solid evidence that saturated fat puts your heart at risk. What isn’t controversial is the link between cardiovascular health and sitting: the more time you spend in your seat, the more your heart attack risk spikes. A study published in the American Journal of Clinical Exercise found inactivity to be responsible for twice as many deaths as obesity, and daily workouts don’t completely undo the damage. So go ahead and enjoy a steak. Just earn it with time on your feet.
You don’t have to stand around all day to fortify your heart. In a study from Melbourne’s Baker IDI Heart and Diabetes Institute, overweight desk jockeys who alternated every 30 minutes between sitting and standing throughout the workday managed to cut their blood sugar levels by 11 per cent, compared with those who sat exclusively.
The sit-and-reach test – sit with legs straight and try to touch your toes – does have some merit: a study at Japan’s National Institute of Health and Nutrition found that people with more flexibility have less arterial stiffness. Unfortunately, the results apply only to people over 40. A better test: grip strength. By following 140,000 adults, researchers linked a weaker grip to increased risks of death, stroke and heart attack. The average middle-aged man should generate about 50kg of force, says study author Dr Darryl Leong. To test your grip, use the dynamometer at your gym or pick up a Camry Digital Hand Dynamometer.
Strengthening your grip alone may not improve your health, says Leong. So address the underlying causes of weakness: poor sleep, lousy diet and lack of exercise. If you just want to bolster your grip, try farmer’s walks: grab the heaviest dumbbells you can and walk across the gym with them.
A glass of OJ with breakfast
Five close friends
In 1970, 1000 milligrams a day of vitamin C – the dose in 1.8 litres of OJ – was believed to protect you from colds. It didn’t. Numerous studies have found no link between C and illness prevention. What does help? Friends. University of North Carolina researchers found that people with robust friendship circles tend to have less inflammation, which can set you up for sickness and worsen the symptoms. According to a Cornell University study, the average person today has two close friends. Aim for five to see an uptick in health, says Dr Robin Dunbar, an evolutionary psychologist at the University of Oxford.
A study of older adults found that those who visited friends or family at least three times a week were 77 per cent less likely to feel depressed than those who hung out only once every few months. Everyone benefits from social interaction, says Dunbar. And no, Facebook doesn’t count.