Regular exercise is a wondrous defence against many health conditions – cancer, dementia, diabetes and depression to name just a few. Missing from that list is heart disease.
To be clear, for many people the link between exercise and cardiovascular health will be overwhelmingly positive.
But the relationship between the two is nuanced and needs careful consideration. We need to look at how cardiac conditions intersect with cycling for riders of different ages and at varying levels of intensity.
The cardiac landscape is obviously different for young adults and Masters (over-40) cyclists. Unless known from childhood, heart conditions are uncommon in young people.
In fact, severe and lethal conditions are so rare that the clinical value of screening for them is outweighed by the logistics.
In contrast, heart conditions are more common in middle age and beyond, so the potential benefits and risks of long-duration and high-intensity cycling for the master’s athlete group need to be evaluated.
Note that the authors of this article, Dr Nigel Stephens and Phil Cavell, are both midlife cyclists. To help explain it all, we’ve used case studies from real patients who have been cared for by Dr Stephens.
- Read more: Fit older male cyclists face these hidden heart risks – here's why that shouldn't put you off riding
Heart attacks, angioplasty and bypass surgery
The most common cause of a heart attack is a blockage to a coronary artery. We all have three arteries that supply blood to the heart’s muscle.
If one contains fatty plaques (atherosclerosis), there’s a risk of rupture and immediate blockage of blood flow to the myocardium. This is a heart attack.
Endurance exercise and statins both exhibit the useful property of making fatty plaques less viscous and more stable over time.
In the long term, cyclists are therefore better protected from plaque ruptures than those who are new to cycling and exercise.
Case study 1
A keen club rider was midway through the regular Sunday ride on rural lanes. Without warning, he veered into a ditch and was found to be in a state of cardiac arrest.
His clubmates performed CPR (cardiopulmonary resuscitation) and called for help. An air ambulance arrived and the man was resuscitated. His ECG (electrocardiogram) showed he’d suffered a heart attack.
He was taken to a cardiac centre, where he had emergency angioplasty (a procedure to widen a restricted artery).
Three months later, the man asked if he was safe to return to riding and, if so, how much and how hard he could ride.
Cyclists often consult a cardiologist with this question, be it after angioplasty or bypass surgery (grafting a blood vessel from elsewhere in the body to ‘bypass’ a blocked artery).
We evaluate how much heart damage is still present and whether the heart’s blood supply is back to normal.
In this case, despite the drama of our patient’s initial illness, his heart was functioning normally and was undamaged. Detailed testing showed its blood supply wasn’t reduced either.
He followed a structured return to training – with increasing volumes of gentle, zone 1 and 2 riding – that allowed him to rejoin his clubmates and return to normal life.
It’s possible that his cycling and resulting fitness helped him to survive the heart attack, and also accelerated his recovery back to full fitness and activity levels.
Leaking heart valves, surgery and high forces in the heart
Wear and tear in the heart valves is a common issue in cardiology. Explosive efforts place huge forces through our heart and raise concern that they may cause or aggravate this degenerative process.
Case study 2
A high-standard track sprinter came to us because of breathlessness. This was initially attributed to lung disease.
However, listening to the heart revealed a leakage of the inlet (mitral) valve between the left atrium and ventricle (two of the heart’s chambers), allowing blood to flow back into the atrium.
An ultrasound confirmed this. While the scan showed the leak wasn’t particularly severe, when we got the cyclist to perform a ramp test on a static bike (where you gradually increase workload), it became torrential during the high-intensity effort, causing him to become short of breath. The valve was repaired surgically and this fix has remained robust for years.
It remains a moot point whether we can aggravate heart-valve decay through cycling. Encouragingly, it appears surgical techniques (and artificial valves) are able to deal with what we can throw at them while pedalling.
Atrial fibrillation (AF)
Sportspeople over 40 have five times the risk of the common heart-rhythm abnormality atrial fibrillation. The biological reason isn’t understood properly, but it may be linked to chronic stretch in the heart’s left atrium – which collects oxygen-rich blood from the lungs – due to thousands of hours in the saddle.
It often starts as brief episodes while riding, seen as an abrupt rise in heart rate with chaotic variation. Riders must slow down, and feel a loss of leg strength and power output.
Untreated, these episodes become more frequent, of longer duration and constant. Nobody likes being told they shouldn’t ride, and it may well make no difference in any case.
For most, medication can safely suppress the AF, but if this is ineffective, ablation works well. This is a keyhole procedure, done under general anaesthetic, which aims to electrically isolate the areas inside the heart that are responsible for generating the abnormal rhythm.
Being male, a Masters athlete, drinking alcohol, stress and experiencing an AF episode are all factors that have been linked to increases in the prevalence of AF.
Hypertension (high blood pressure)
When we exercise, our blood pressure rises by 50% and doesn’t cause any harm. But for some, dangerous hypertension is mainly (or only) seen during sustained exercise.
And if we ride for 10 to 20 hours a week – 5% to 10% of our life – there’s an appreciable risk. Modern blood-pressure medication is safe and, for the most part, free of side-effects, and can effectively mitigate this risk.
Covid and Long Covid
In 2020, the cardiology community held its breath – would we see an epidemic of myocarditis (heart muscle inflammation) and damaged hearts? The answer six years down the line is a definite no. But issues certainly exist.
Case study 3
A young aspiring professional cyclist was laid up for a week with Covid-19 in 2020. He recovered and soon attended a training camp, but couldn’t perform at his previous standard. His FTP (functional threshold power) was down by 20% and training proved exhausting.
Autonomic nerve testing showed marked abnormalities, and we concluded the issue was a malfunction of the arteries feeding blood to the working muscles.
This athlete’s rehabilitation included a staple of zone 1 training, as well as physio-supported mobility and core work. After 18 months, he returned to full training, edging closer to his potential and peak performance.
This young athlete’s experience has been a recurring theme for elite sportspeople who’ve apparently recovered from Covid but have been unable to perform at their previous levels.
Their prognosis is good, but recovery can be slower than you’d expect, given their youth and fitness. Even at pro-team level, the return to full performance and resilience has often been a rollercoaster, where an athlete might ride on one day and feel fine, but then experience a week of debilitating fatigue.
When your job is high-performance, this must be agonising. It seems that pushing too hard can carry consequences.
Heart-health takeaways
- Exercise is good for your health, but how much and how hard isn’t completely clear. Adopt a rational personalised approach – Masters and older athletes should get a QRISK score (a widely used clinical calculator used to predict the likelihood of cardiovascular disease in the next 10 years) as a basic minimum.
- If you’re new to cycling or returning after a long lay-off, it’s a good idea to have a consultation with a health professional before you start. Silent conditions may appear without warning.
- Treated heart disease doesn’t mean you can’t return to exercise and even competitive sport, but it’s important to get a cardiology evaluation beforehand.
- Atrial fibrillation occurs more often in Masters sportspeople. But it’s treatable and shouldn’t prevent you exercising.
- Recovery after Covid can sometimes be frustratingly slow, but the prognosis is good for most people.
This article was written jointly by Dr Nigel Stephens (consultant cardiologist and international Masters cyclist) and Phil Cavell, founder of Cyclefit and author of 2021 book The Midlife Cyclist: The Road Map for the +40 Rider Who Wants to Train Hard, Ride Fast and Stay Healthy
