Get outside! It’s on the doctor’s orders

With temperatures dropping and the sun seemingly setting before you’ve even finished your lunch, it’s tempting to hang up the gardening gloves and let the trowels gather dust.

The garden can wait, right? Well, not really. An estimated 27 million Britons now garden regularly, but it’s far more than a hobby or a way of keeping the borders neat and tidy. It’s a chance to enjoy fresh air, natural movement, bright outdoor light and even stress-relieving plant chemistry.

While skipping the usual digging, planting and pruning might seem fairly harmless, your body feels the difference more deeply than you might realise.

You’re probably familiar with the impact of staying indoors on muscles and bones; they stiffen and weaken, plus, with less movement, your metabolism slows, making weight gain easier.

But that’s only the beginning. The average Briton spends just seven per cent of their time outdoors during the work week, according to research by Loughborough University, which author and psychotherapist Eloise Skinner says isn’t typically enough for the body and brain if we want to feel our best.

“We were literally made to spend time outside,” says Skinner. So, what could really happen if you stay in all winter?

Your sleep suffers

Good sleep is the cornerstone of good health, with adults recommended to get seven to nine hours a night. However, the average Briton only gets three days a week of decent-quality sleep, according to a study by the Mental Health Foundation. Steering clear of the garden might make sleep even harder.

“Sunlight is one of the main signals for your body clock,” says Dr Chun Tang, GP at Pall Mall Medical. “Even on a grey winter day, outdoor light is much stronger than indoor lighting, and that’s enough to tell your brain, ‘it’s daytime now’.”

This helps to set your circadian rhythm, your body’s internal 24-hour clock, which tells you when to feel sleepy and when to wake up. It also influences your appetite (which is why you don’t usually feel hungry at 2am), your hormones, and even your body temperature.

Outdoor light is 10 to 100 times brighter than indoor light. Measured in lux, a unit that measures how much light reaches your eyes or a given surface, even a cloudy day can measure at 2,000 lux, while a bright indoor light might reach just 500 lux.

“It doesn’t have to be bright or sunny; just being outside, even under clouds, gives your brain a clear ‘daytime’ message,” says Dr Tang.

“When you don’t go outside, your body clock stops getting those strong signals. Your brain can’t clearly separate day from evening, so you can end up feeling tired and heavy during the day but not properly ready for sleep at night.”

Melatonin, the hormone that tells your brain it’s bedtime, becomes mistimed, too. “It can feel a bit like mild jet lag where you’re groggy in the morning but wide awake later in the evening,” says Skinner. Cue, lying awake at night, ruminating over your day or worrying about tomorrow’s to-do list.

And when you do sleep badly? Many of us have experienced the off-kilter feeling that kicks in the next day. Pair that with another day of being indoors, and it becomes a vicious circle.

In a 2018 YouGov report, 66 per cent of people said daylight significantly impacts their mood. Another smaller study in the journal Building and Environment asked participants to rate 3D simulations of various ‘daylight-improved’ home designs. The simulations in which more daylight entered the home significantly increased perceived emotional well-being, and participants said they felt happier or less sad under well-lit conditions.

“Indoor air is also staler, you’re usually looking at close-up screens, and you tend to move less, which means less blood flow and less oxygen getting to your brain, causing poor concentration, slower thinking and lower mood,” says Dr Tang.

“When you move, the lining of your blood vessels releases a substance called nitric oxide, which helps your blood vessels relax and widen, says Dr Tang. “If you sit indoors for long stretches, you produce less nitric oxide, your vessels stay tight, and your body has to work harder to move blood around. Over time, that matters for heart and vascular health, not just for how energised you feel in the moment.”

But, Dr Tang adds that if you’re getting plenty of daylight and movement, yet you’re still feeling lethargic and struggling to move about, seek medical advice.

You’ll miss out on immune-supporting chemicals

The plants in your garden aren’t just there to look pretty; there’s another benefit that people rarely talk about.

“Plants release microscopic compounds into the air called phytoncides. So, when you’re out in a garden or among trees, you breathe some of these in,” says Dr Tang.

These natural chemicals protect the plant, but they also benefit humans. Research around phytoncides is compelling. An investigation published in the journal Environmental Health and Preventative Medicine found that when human NK cells (a type of immune cell that fights virus-infected cells and tumours) were exposed to phytoncides, there was an increase in the cytolytic activity of the NK cells. This means the NK cells were better at destroying harmful cells, in turn, bolstering your immune system.

Another study in the Journal of Exercise Rehabilitation, split a group of 55 women into two groups: a control group with no phytoncide exposure and a group who were exposed to phytoncides. The latter group experienced a nine per cent reduction in stress levels and a 25 per cent reduction in the stress hormone, cortisol. The control group showed no reduction in either of these measures.

“That’s part of why people often feel more relaxed and clear-headed after time in green spaces, even if they weren’t doing anything strenuous,” says Dr Tang.

You don’t need to spend hours outside during winter. Just ten to 20 minutes outdoors can make a real difference to your sleep, mood, energy and health.

“It might be cold, but if you can push past that, try to see it as giving your brain and body a reset,” says Skinner.