Is our fixation on fitness getting dangerous?

As Ireland forges its supersized-way to becoming Europe's fattest nation by 2030, the need for at least 150 minutes of moderate exercise a week is being justifiably flagged by health professionals far and wide, but what of the dangers of over-exercise?

Enter the world of the weekend warrior and the unheralded rise of endurance sports in Ireland. Written of as a fringe, if not looney, preoccupation as recently as the 1990s, endurance sports have since become very much mainstream for the over-30s in particular.

Be it running, cycling or swimming (or, less common, rowing, horse riding or cross-country skiing), endurance technically caters for all distances greater than 800m, although it more often relates to the 10km range upwards (for swimming, 1-1½km signifies the endurance crossover).

While marathons have been a burgeoning presence on the Irish sports calendar over the last 30 years, since golf addiction abated in the noughties there seems no end to the seemingly unstoppable growth of cycling and multi-sport events (for example, triathlon or ironman, or the multiple Gaelforce or Quest events held each year in Ireland).

However, if taken to extremes, endurance sports have the capacity to prove ultimately more damaging to our health than no exercise at all.

Harder challenge

"You can be fit without being considered healthy. You might do the training, but your lifestyle could be poor," says Dr Micheál Newell of the Clinical Science Institute at NUI Galway. An exercise scientist specialising in lifestyle medicine, Newell says damage can sometimes arise from the type of training being pursued, rather than the immense amount of it.

“With so many types of exercise, people get into it and enjoy it. Then they start to enjoy a harder challenge. If you talk about ultra-marathon runners, for example, they want more – a new challenge. But the trade-off may be they’re exposing themselves to early-onset arthritis, damage to their knees or their joints. And for female athletes, they could be putting their menstrual cycle in trouble,” says Newell.

And male endurance athletes often fare worse, according to a 2008 article in the Journal of Endocrinological Investigation, which claimed that "an increasing number of investigative research studies point to participation in endurance exercise training as having significant detrimental effects upon reproductive hormonal profiles in men".

When does exercise become over-exercise?

"It really is individual, based on what someone has done before. But the actual answer is we don't know what the optimal is," says Dr Fiona Wilson, chartered physiotherapist and associate professor of Physiotherapy at Trinity College's School of Medicine.

“The sustainable activity is the optimal activity, as it should be adapted as a lifestyle as you get older. Your heart will adapt to exercise in a good way, but it can only do that for so long. What we’re seeing now are a number of elite athletes having cardiac problems, specifically atrial fibrillation.”

While it may not be fatal, atrial fibrillation is a serious, abnormal heart rhythm typically affecting less than 2-3 per cent of the population. Characterised by rapid and irregular beating of the heart, it can be accompanied by light-headedness, shortness of breath or chest pain, while being associated with an increased risk of kidney problems, heart failure and stroke.

It can create a reduced cardiac output, meaning the heart is unable to provide adequate blood flow, and therefore oxygen, about the body. It can last from seconds to 48 hours, starting as a once-off, before becoming more regular until, if left untreated, eventually it becomes permanent.

“One of the increased risks we are seeing this is in people who have taken up ironman in middle age. It’s a new phenomenon, especially for people who have hit 40, and it’s grown in popularity. The cardiac muscle just cannot adapt to such a degree,” says Wilson.

“Graduated exercise may be the best way to go about it, because as you get older the heart muscle doesn’t adapt to exercise as well, depending on how much you’ve been doing up to that point. But the human heart was never designed for such massive volumes [as ironman]. Just make sure you’re in good cardiac health before beginning any endurance training programmes – get yourself checked out by a good doctor,” says Wilson.

Heart of the matter

Cardiologist Sanjay Sharma of St George's University in London knows a thing or two about how a sporty heart ticks. Specialising in sports cardiology, among many other distinctions he also serves as cardiologist for the Lawn Tennis Association, the British Rugby Union and the English Institute of Sport Congress.

According to a talk given by Sharma to a Sports Science and Medicine Conference in the UK in 2015, up to half of endurance athletes have hearts that are larger than the general population; a condition which can, in some circumstances, be associated with sudden death syndrome that can affect younger athletes, in particular.

But the over-40s have more to fear. Citing recent studies, Sharma said the risk of atrial fibrillation is five-fold greater in 40- to 60-year-old endurance athletes than middle-aged people who don’t exercise much at all.

He also revealed that middle-aged athletes are also more susceptible to sinus node disease, where the sinus node (the heart’s primary pacemaker) doesn’t properly function, or where the heart may not beat for up to five or six seconds, requiring some to need pacemakers in their 60s and 70s.

"The big thing to keep in mind is that it's a totally different thing between peak performance or peak fitness, and exercise for conferring longevity and overall health," Dr James O'Keefe told an Annual Ancestral Health Symposium in the US in 2012. A self-described "lifelong exercise aficionado" and former marathon runner, O'Keefe is the director of preventative cardiology at the Saint Luke's Mid America Heart Institute in Kansas City.

Aside from a five-fold increase in atrial fibrillation, O’Keefe said research shows that chronic marathon runners (that is, those who ran at least one marathon a year for the previous 25 years) have twice the coronary plaque in their arteries and twice the risk of heart attack and sudden death than sedentary people. He added that under no circumstance in our ancestry would we have been running 26 miles.

Rather, he believes we are born to walk, contrary to the 2009 bestseller, Born to Run, which has, three million copies later, been widely adopted by the global running community as their 21st century running manual, while generating unprecedented interest in ultrarunning.

What's less well known is that in 2012 one of the pivotal characters in Born to Run, ultrarunner Micah True, died while running. He was aged 58. While inconclusive about the cause of his death, the autopsy revealed True suffered from idiopathic cardiomyopathy (ie a disease that affects the heart muscle), causing his left ventricle to become enlarged.

O’Keefe said he advises his patients who are hoping to run in a marathon to try “something that’s healthy for you”. Simply put: running is unquestionably good for us, but running too long or too often is not.

Take the 35-year long research at the Cooper Clinic in Dallas, O'Keefe pointed out, which monitored the health of 50,000 subjects over three decades. It concluded that runners had a 19 per cent lower risk of death than non-runners, but those who ran at moderate speeds, distances and frequencies came out with the best health. Notably, the study claimed the ideal running distance was between 5 miles and 20 miles (or 8km to 32km) per week.

Puns aside, the Kansas cardiologist “heartily endorses” strenuous exercise as long as it is limited to 30-60 minutes a day (with about 45 minutes being the sweet spot), or a maximum of seven hours a week, especially once over 40. And don’t forget the value of cross-training, such as resistance training, yoga, Pilates or high-intensity interval training (or HIIT), he concluded.

Thinking health and longevity? Think muscle

"Higher levels of muscle decrease the risk of mortality," Dr Preethi Srikanthan tells The Irish Times. The endocrinologist and health sciences associate clinical professor of medicine at UCLA in California is the author of the 2014 study "Muscle Mass Index as a Predictor of Longevity in Older Adults".

“In previous studies, we noted that greater muscle mass is associated with improved insulin resistance, which is at the root of both diabetes development and cardiovascular disease risk. Hence, we wished to assess whether muscle mass influenced risk of death. We can now say that muscle mass seems to be an important predictor of risk of death,” she says.

Srikanthan says resistance exercises will help increase muscle mass and people can either use light weights, or else floor exercises such as push-ups, leg lifts or plank holds.

Nine ounces a year, and counting

"Extreme endurance sports will increase muscle wastage," says Keith Begley, accredited sports psychologist with the Irish Institute of Sport and a former physical education teacher. "So if you are doing those sports it's important you are also doing strength or resistance training to maintain muscle mass, as well as taking appropriate levels of protein.

“As you get older, you need muscle mass to maintain your strength and balance. There is a physical problem, which might not have hit these people yet, but will do when they get into their 60s or 70s. They might be burning fat and losing weight now, but a lot of the weight they’d be losing is good healthy muscle,” says Begley, who advocates endurance athletes do regular core training, including pilates, as well as resistance training such as with TRX, kettlebells and light weights.

“Otherwise, you’re accelerating frailty long term. This means that if you’re hitting 65 or 70 you’re accelerating the chances of arthritis or osteoporosis, for example. You’d be best to cut back on aerobic training and up your anaerobic training to maintain muscle mass.”

The cardio/muscle mass balancing act

"If there is not enough muscle mass particularly on the back, to hold the body up, the muscles relax to allow the skeleton hold the body up," says Ronan Murphy, a strength and conditioning expert and owner and manager of TonedFit gym in Howth.

“That’s one of the reasons why there are so many issues with backs, knees, hips and shoulders, because the emphasis is being put on the joints, rather than the muscles around them. So you need to start bringing in resistance to stimulate your body to be able to deal with movement and resistance outside of your own comfort zone.”

In men, such resistance stimulates muscle mass, in women it is muscle density. Regardless, says Murphy, such muscle is of crucial importance for all endurance athletes.

“If there is more muscle on the body than required, you’re sending oxygenated blood down to extended muscle, meaning you will tire quicker. But if there is not enough muscle, it needs to work even harder, meaning harder breathing and a faster pulse rate. So it’s a balancing act to find the right amount of muscle in order to work in the most efficient way possible.”

Sign up for one of The Irish Times' Get Running programmes (it is free!).

First, pick the programme that suits you.
- Beginner Course: This programme is an eight-week course that will take you from inactivity to being able to run 30 minutes non-stop.
- Stay On Track: The second programme is an eight-week course for those of you who can squeeze in a 30- to 40-minute run three times a week.
- 10km Course: This is an eight-week course designed for those who can comfortably run for 30 minutes and want to move up to the 10km mark.
Best of luck!