Cork Views: Why a swim is good for your mind and body

Every summer, off Glen Pier in Ballinskelligs, I swim in water so cold, it makes my bones ache and teeth chatter. I swim through the waves to the stone steps hallowed into the rock on the opposite side, and lie on my back in dappled sunlight, the Skelligs shimmering in the distance. It feels better than almost anything else.

It’s good for my brain space, strength, breathing, heart, lungs, balance, sleep, creativity, and most of all my sanity.

You may have heard experts recommend that adults get 150 minutes of moderate activity or 75 minutes of vigorous activity every week. Swimming is one of the best ways to work your entire body, including heart and lungs.

One of the biggest benefits is that it works your entire body from head to toe. It increases heart rate without stressing the body. It tones muscles, builds strength and endurance. Each stroke builds on different muscle groups and the water provides a gentle resistance.

But no matter what stroke, you are using most of your muscles groups to propel you through the water. While muscles are being given a work-out, swimming also makes the heart and lungs work hard.

Swimming is so good for you that there is evidence of risk of death in swimmers being about half of that for non-swimmers, including those who are walkers or runners.

Research has also shown swimming is good for lowering blood pressure and controlling blood sugar.

While it is important to have a doctor’s approval before beginning any exercise programme if you have underlying medical conditions, swimming has been shown to be a safe exercise option for most people with arthritis, injury, disability or other conditions that make high-impact exercises difficult.

It can help reduce pain and improve recovery following an injury. One study in the Journal Of Rheumatology (2016) showed that swimming can reduce pain and joint stiffness in people with osteoarthritis.

The humid environment of pools can make swimming a good option for people with asthma, and the breathing exercises associated with the activity can improve lung capacity and in gaining control over breathing.

Swimming can be good for people with multiple sclerosis too. The water makes limbs buoyant, helping support them during exercise as well as providing gentle resistance. A study in Evidence Based Complementary Alternative Medicine (2011) reported a 20-week swimming programme resulted in significant reduction of pain as well as improvements in symptoms like fatigue, depression and disability.

A key benefit of regular swimming is its impact on sleep. In a study of older adults with insomnia published in Sleep (2011), participants reported both a boost in quality of life and in sleep after engaging in all types of regular exercise including swimming.

The activity is also relatively inexpensive compared to other exercises. Many pools offer reasonable rates to join as well as reduced rates for the over 65s. Some public pools offer swim hours for free and some employers offer special rates to join a fitness centre or pool.

Swimming is an excellent way to burn calories. Many people’s first thought when they want to lose weight or tone up is to join a gym. But you don’t have to hit the gym to transform your body. In fact, you might have better results with activities you enjoy, like swimming.

A 160lb person burns about 423 calories an hour while swimming at a low or moderate pace. Pushed up to a more vigorous pace, it can increase to 715 calories an hour.

In comparison to other popular low-impact activities, walking at 3.5 miles per hour for 60 minutes burns about 314 calories, while yoga might burn just 183 calories per hour.

Taking a swim class to maximise your technique, as well as stepping outside your comfort zone and modifying your routine, are excellent ways to use different muscle groups, helping to maximise your results.

To keep weight in check, the more physically active you, are the better. Whether you’re walking, jogging, using cardio equipment or swimming – aiming for four to five times a week is recommended for best results.

The experts recommend starting with 15-20 minutes every other day, gradually increasing to 30-minute swims, five days a week, as your body allows. If you start a new swimming routine at too high an intensity, muscle soreness and fatigue could cause you to give up before you really get going.

Over a century ago, in 1905, the benefits of exercise as a treatment for depression were documented in the inappropriately named American Journal Of Insanity. Since then, the brain chemicals released during exercise that prevent and treat depression have been discovered. These included opiates, cannabinoids and endorphins as well as brain-derived neurotrophic factor (BDNF).

Professor Rose Anne Kenny, in Age Proof, outlines how exercise confers additional benefits, like self-esteem, a sense of achievement, being in control and having a purpose as well as adding variety, social engagement and interaction with friends.

“Most of us have experienced feeling too tired to move, happily slumped in front of the telly, before forcing ourselves to take a walk. On return, we feel revived and invigorated. Exercise makes us feel good, and this is so even if we are depressed.”

Not only does exercise help prevent and treat depression, new evidence in brain science shows how exercise can grow new nerve cells. Over the past two decades, it has become clearer how this occurs.

Prof Kenny outlines how exercise increases the size of the hippocampus, the seat of learning and memory in the brain. Normally, it shrinks in late adulthood – the number of nerve cells start to decline, leading to impaired memory and ultimately risk of dementia.

“Physical activity slows down hippocampal shrinkage. Even in older adults, studies have shown aerobic exercise training increases the size of the hippocampus, leading to improvements in memory. Exercise training reverses the age-related loss in volume by as much as two years - nothing else has such a dramatic effect.”

Best of all, when I am swimming in the sea or a pool, everything is turned off. All those emails and tweets and reminders and WhatsApp messages, all the external noise that distracts and the internal reminders that push into your frontal lobe for immediate attention.

There is something very special about that gliding motion up and down, friction-free, that puts everything else on hold while you control your breathing and move rhythmically and smoothly through the water.

Dr Catherine Conlon is a public health doctor and former director of human health and nutrition at Safefood.