Steering clear of the gym? Here's how to exercise outdoors and stay fit this winter
Winter is creeping up on us, so get prepped for some chilly outdoor jogs, breezy bike rides and breath-sapping swims. Gyms in locked-down Wales have been forced to close. With more areas expected to go into Tier 3 lockdowns, indoor training could be out of the equation this winter. The government seems worried that gyms could become super-spreader venues, following the high-profile outbreak of 69 cases of Covid-19 at a cycling studio in Hamilton, Canada. Public Health England’s own Test and Trace data suggests gyms are, at best, a third as “hazardous” as pubs. But even some fitness enthusiasts won’t want to gulp recycled air in a gym this winter.
Whether through personal choice – or a lack of it – most of us will be exercising outside with rosy cheeks, foggy breath and frozen hands. This will feel much harder than during the balmy spring lockdown. But with obesity increasing the chances of dying from Covid-19 by 90 per cent, and exercise proven to mobilise our immune cells, it’s essential that we keep moving.
Professor Mike Tipton of the Extreme Environments Laboratory at the University of Portsmouth insists we shouldn’t fear the cold. “So long as you’re generating more heat than you are losing, you'll be okay,” he explains. “And in most cold conditions, people who are exercising will achieve that.”
The normal temperature of the human body is around 37°C. When you exercise in the cold, your metabolism and heart rate rises, and you burn extra calories to stay warm. During exercise your metabolism can surge 20-25 times higher than while at rest, and your body can produce 1-2 kilowatts of heat. “That's the equivalent of a one- or two-bar fire inside you,” says Prof Tipton.
How hard you need to exercise depends on what you’re wearing and how cold it is. But studies suggest 60 per cent of your VO2 max (a measure of your maximal oxygen uptake) is about right: that’s a medium intensity, so you can still hold a conversation but feel quite puffed. A person can maintain a core temperature above 35°C for seven hours if they exercise at 60 per cent of their VO2 max. And studies in the British Medical Journal and the American Journal of Physiology suggest that even in wet 5°C conditions, people who train at 60 per cent of their VO2 max perform as effectively as in milder conditions.
But one of the most common mistakes is to go out cold. A 15-minute warm-up indoors, which raises your body temperature by just a third of a degree, is enough to stoke your furnace before you leave. “I’d warm up at home on the bike rollers then wear extra layers to keep warm at the start,” explains Prof Tipton. “We hate taking layers off 20 minutes in, but that attitude is a mistake. You need to keep warm until you've generated enough heat for your body (heat) to take over.”
Clothing choice is particularly important over winter. “There's a saying by Dave Bass (a physiologist at Yale University) back in the Seventies: “A man in a cold environment is not necessarily a cold man.” That sums it up: it is your tissue temperature that matters – not the environmental temperature.”
To create a toasty “microclimate” around your body, you need to trap warm, dry air close to your skin with a base layer, warm tights and a thermal jacket. Prof Tipton suggests you cover your head when temperatures drop below 5°C; choose moisture-wicking fabrics to prevent sweat cooling your body; and use clothing with tight seals to prevent cold air seeping in. All your gear should be windproof: at 4°C, the wind chill from 20mph gusts will drag the temperature down to the equivalent of minus 7°C.
For some of us, even woolly socks and ski gloves can’t prevent chilly extremities. Studies suggest women’s fingers cool faster than men’s, possibly due to relative hand size. “You can wear gloves but the primary source of heat to a hand and a foot will always be the blood flowing into it,” advises Prof Tipton. “Your body shuts down blood flow to the hands and feet in order to maintain deep body temperature by drawing blood beneath the body's fat, which has the same thermal characteristics as cork. So to avoid cold hands, warm up before you leave the house and stay warm when you’re out.”
Your arms are also vulnerable to cooling, due to their high surface area to mass ratio, and the proximity of nerves close to the skin, so keep them covered. On really cold days, wear a thin buff over your mouth: inhaling cold air can irritate the lining of the upper respiratory tract and trigger flu-like symptoms, such as a runny nose or dry cough – enough to worry strangers in the pub right now.
Outdoor swimmers enjoy amazing mood-boosting health rewards over winter but they also face the biggest challenges: humans cool two to five times more quickly in cold water, compared to air at the same temperature. But it helps if you take the plunge more often: research suggests that after just 5 × 3-minute immersions in cold water, swimmers enjoy a 40 per cent reduction in their cold shock response. “We tested Channel swimmers 14 months later and they were still better off,” adds Prof Tipton.
According to nutrition consultant Richard Tucker of The Human Performance Lab, you should top up your carb intake during winter training. “Cold-induced thermogenesis (CIT) means your body begins to burn more calories to keep warm,” he explains. “This may see an increased demand on carbohydrate oxidation as carbohydrates become the preferred source of energy. Cool weather can also upset digestion and the ability to transport nutrients as there is reduced blood flow to the gastrointestinal tract. Therefore you may wish to opt for (easier to digest) semi-solids such as gels, or food with a high moisture content, such as bananas, malt loaf or homemade flapjacks.”
Cold weather also blunts your thirst reflex, so always hydrate before and during your workout. Professional cyclists carry flasks of warm lemon cordial over winter to entice them to sip more often.
