Running: How It Affects The Heart, Bone Health, Risk Of Atherosclerosis And More

Can a single minute of exercise each day lead to better bone health in women? Yes. Scientists from the University of Exeter and the University of Leicester found those who did “brief bursts” of high-intensity, weight-bearing activity equivalent to a medium-paced run for pre-menopausal women, or a slow jog for post-menopausal women, had better bone health.

Using data from UK Biobank, the researchers found that women who on average did 60 to 120 seconds of high-intensity, weight-bearing activity per day had four percent better bone health than those who did less than a minute.

“We don’t yet know whether it’s better to accumulate this small amount of exercise in bits throughout each day or all at once, and also whether a slightly longer bout of exercise on one or two days per week is just as good as one to two minutes a day,” said lead author Dr. Victoria Stiles, of the University of Exeter. “But there’s a clear link between this kind of high-intensity, weight-bearing exercise and better bone health in women.

“Because this is a cross-sectional study – which assesses data taken from a subset of the population at a particular point in time – we can’t be sure whether the high-intensity physical activity led to better bone health, or whether those with better bone health do more of this exercise,” Stiles continued. “However, it seems likely that just one to two minutes of running a day is good for bone health.”

Good Bone Health Benefits

The researchers looked at data on more than 2,500 women and compared activity levels – measured by wrist-worn monitors – with bone health -measured by an ultrasound scan of heel bone. As well as finding four percent better bone health among women who did one to two minutes of high-intensity, weight-bearing exercise, they found six percent better bone health among those who did more than two minutes a day.

Stiles said the data from UK Biobank – taken from monitors worn for a week – was broken down into single seconds to understand how people go about their daily activities. “We wanted to make every second count in our analysis, because short snippets of high-intensity activity are more beneficial to bone health than longer, continuous periods,” she said. “We were careful not to ignore short bursts of activity throughout the day.”

As a suggestion for anyone interested in increasing their day-to-day levels of activity, Stiles said: “The UK’s National Osteoporosis Society recommends increasing your walking activity first. Further on, we would suggest adding a few running steps to the walk, a bit like you might if you were running to catch a bus.”

Good bone health has multiple health benefits, including a reduced risk of osteoporosis and fractures in older age.

Running Marathons And Risk Of Athersclerosis

Running multiple marathons does not increase the risk of atherosclerosis, according to research published last summer in the European Journal of Preventive Cardiology.

“There has been a debate over whether intensive endurance exercise such as marathon running may be dangerous for the heart,” said lead author Dr. Axel Pressler, Head of the Prevention Centre, Technical University of Munich, Germany. “Previous studies found that after running a marathon, the same cardiac biomarkers were acutely elevated as after a heart attack. Other research discovered increased coronary atherosclerosis in marathon runners as a potential chronic consequence of running. However, this may have been due to exposure to traditional risk factors such as current or past smoking.”

This study aimed to find out whether running itself could induce the early development of atherosclerosis. It therefore included only healthy men without any history of cardiovascular risk factors such as cardiovascular disease, hypertension or smoking. Pre-atherosclerotic changes to the function and structure of the blood vessels were evaluated by increased stiffness of the arteries, increased intima-media-thickness – due to early atherosclerosis – and endothelial dysfunction, which indicates an impaired reaction of the vessel to blood flow.

Marathons And Blood Vessels

The study included 97 participants of the 2013 Munich marathon who had already completed multiple events. Each participant did an exercise capacity test to measure peak oxygen uptake, and gave their training history. The finishing time for the marathon was recorded for each runner. Measurements of arterial stiffness, intima-media-thickness, and endothelial dysfunction were taken before and after the event.

Prior to the current marathon, participants had successfully finished a median of 11 running events which included half marathons, full marathons, and ultramarathons. The average weekly and annual training distances were 59 kilometers and 1, 639 kilometers, respectively.

Runners had normal mean values for arterial stiffness, intima-media-thickness, and endothelial dysfunction. There was no association between exercise capacity, marathon finishing time, number of completed races, or weekly and annual training distances with arterial stiffness, intima-media-thickness, or endothelial dysfunction. The only characteristic of the runners that was independently associated with the three measurements of pre-atherosclerosis was age.

“When we get older our arteries get stiffer and are not so elastic anymore,” said Pressler. “Our study shows that runners who have finished 20 marathons do not have stiffer arteries or more impaired vessel function than people of the same age who have finished five or zero marathons. We can conclude that marathon running itself is not a risk factor for atherosclerosis. It appears that you can run as many marathons as you want and not be in danger of developing impaired blood vessel function or atherosclerosis.”

While running multiple marathons did not have a deleterious effect on the blood vessels, it did not have a positive effect either. Pressler said: “Running had a neutral effect on the blood vessels. The state of the blood vessels in these runners depended solely on their age.”

The findings are good news for runners, but Pressler warned that marathons do put strain on the body and participants should ensure they are prepared through training, nutrition, and appropriate hydration. “Many people are interested in marathon running and are doing ambitious recreational sports. Our study shows that running multiple marathons is not risk factor for atherosclerosis.”

Is Running Good For The Heart?

Other news stories about runners suffering sudden cardiac arrest (SCA) and other heart-related complications mid-race might leave some wondering if there may actually be a risk to running. Last year ABC News reported about a man who had an SCA while running the Key West half marathon, The Telegraph shared news of a runner in the London marathon who collapsed three miles before the finish line in 2016, and Philadelphia Magazine reported in 2015 that two athletes suffered an SCA during the Broad Street Run.

“Running, or any kind high-intensity exercise, puts a strain on the heart muscle, as it does on lung tissue, and leg and arm muscles,” said Neel Chokshi, MD, an assistant professor of Clinical Cardiovascular Medicine, and medical director of the Penn Sports Cardiology and Fitness Program. “While evidence suggests an increased risk of cardiac events during high intensity exercise, the overall likelihood of such events is ultimately very, very low. There is more far research to support running and exercise as a benefit to heart health, rather than a detriment.”

The World Health Organization suggest that adults ages 18 to 64 do at least 150 minutes of a moderate exercise or at least 75 minutes of high-intensity physical activity each week. Guidelines also recommend adding muscle strengthening exercises into the routine two or more days per week.

Based on these recommendations, a casual runner could log eight miles per week at about a nine-minute mile pace. But what about someone training for something more rigorous, like a marathon, or triathlon? Is there more risk for competitive athletes, who run say 20 to 40 miles a week – or 210 to 300 minutes of vigorous exercise – effectively tripling or quadrupling this recommendation?

Progressive Training Is Key

“It’s important to understand that the likelihood of cardiac events is greatest in those individuals who have a low baseline level of physical activity and suddenly jump into moderate to high intensity exercise,” Chokshi said. “So, as long as you train in a progressive manner, gradually increasing mileage, pace of a run, or amount and type of exercise, and you listen to your body, your heart and lungs will adapt at the same rate. This will allow you to continue your training while minimizing risk of injury to both your heart and other muscles.”

And this same advice applies to anyone looking incorporate more exercise into their routine. Everyone should be aware of the possible risks and listen to their bodies, but the most important thing is engaging in some level of activity each day or week – which has been shown to have immense heart and overall health benefits.

A recent study published in JAMA Internal Medicine found that even those who exercised for fewer than the recommended time – 150 minutes of moderate or 75 minutes of vigorous exercise per week – showed a decrease in risk of death, when compared to those who had little to no physical activity each day. Researchers concluded that any amount of physical activity lowered risk of death, specifically from heart disease, by approximately 40 percent, as compared to those who led a sedentary lifestyle.

In an Associated Press article about the study, Daniel Rader, MD, chair of Genetics and director of Penn’s Preventive Cardiovascular Program, said, “People who exercise more regularly report that they feel like they have a better quality of life,” among other benefits. However, even if you only have time to do something once a week, this study would suggest it’s still worth doing.”

A Preventative Measure

This seems promising for those who find 150 minutes of exercising to be daunting, for those who are coming back from an injury, or those looking to take the first step toward leading a more active lifestyle. The main message seems to be that anything is better than nothing. But for some, the question of how to minimize any risk from exercise still remains.

“In general, most individuals who increase their workouts gradually and feel well while doing so are at low risk and require no medical evaluation,” Chokshi added. “But, patients with pre-existing heart conditions or those who experience heart-related symptoms such as chest pain, shortness of breath or palpitations during exercise, may be at increased risk during exertion. This group should work in closely with their physician to understand risk factors, determine if any pre-exercise testing is needed, and to create an exercise regime that can help reduce risk of an exercise-induced cardiac event, while still maintaining a healthy lifestyle.”

But if most people have little to no risk for a cardiac event while exercising, why has there been so much buzz linking exercise to sudden cardiac arrest? As a 2016 paper from the American College of Cardiology’s (ACC’s) Sports and Exercise Cardiology Leadership Council points out, “the public media has embraced the idea that exercise may harm the heart and disseminated this message, thereby diverting attention away from the benefits of exercise as a potent intervention for the primary and secondary prevention of heart disease.”

So perhaps we don’t need to cut back on exercise, but instead need to read past the headlines to understand what is really good or bad for our hearts. For Chokshi, the recommendation to exercise as a preventative measure will continue, as will his focus on clinical and research efforts evaluating the effects of rigorous, and regular, exercise on the heart.

Running, Lifting Weights And Reducing Injury

Experts say a few sessions in the weight room can improve your abilities while reducing your chance of injury. Finding time for strength-training exercises can be difficult for runners with busy schedules. Lifting weights doesn’t have to be time consuming, and runners can follow workout routines that take less than 20 minutes to complete.

The results are well worth the time. “Lifting weights can make a big difference for runners,” says Chris Kolba, a physical therapist at The Ohio State University Wexner Medical Center. “In a nutshell, the weight training will give your running muscles more strength, which improves athletic performance and reduces your risk of injury. It’s all about the forces your feet and legs experience while you are running. Your foot is on the ground for maybe a tenth of a second, but during that time it’s handling five to eight times your body weight.”

Strength training also increases your body’s ability to both absorb shock and control motion. This improves your athletic performance while also significantly reducing the risk of injury.

Protect Your Legs With Fewer Distractions

Runners who encounter visual and auditory distractions may be more likely to sustain leg injuries, according to research from the University of Florida presented last year at the Association of Academic Physiatrists Annual Meeting.

The team looked at the effect of auditory and visual distractions on 14 runners to determine what effect, if any, distractions would have on things such as how much a runner breathes per minute and how much of that oxygen is utilized by the body, heart rate, the amount of energy expended, running rhythm, the length and width of steps, the speed in which runners apply force to their bodies, and the force the ground applies to the runners’ bodies when they come in contact with it.

“There isn’t a lot of research that looks at the connections between cognitive stressors, or distractions, and injury risk, says Daniel Herman, MD, PHD; assistant professor at University of Florida Department of Orthopedics and Rehabilitation and lead investigator in the study. “This is an important topic to study as runners commonly attend to distractions such as music, crowd noise, or other runners.”

Running Environments

The runners – eight men and six women – were all injury free at the time of the study, and they were approximately 26 years old. On average, the runners logged 31 miles each week.

The team had each participant run on a treadmill three separate times. The first time was without any distractions. The second time added a visual distraction, which consisted of the runner concentrating on a screen displaying different letters in different colors with the runner having to note when a specific letter-color combination appeared. The third time added an auditory distraction similar to the visual distraction, with the runner having to note when a particular word was spoken by a particular voice.

When compared to running without distractions, the participants had faster application of force to their left and right legs – called loading rate – with auditory and visual distractions. They also experienced an increased amount of force from the ground – called ground reaction force – on both legs with auditory distractions. Finally, the runners tended to breathe heavier and have higher heart rates with auditory and visual distractions than without any distractions at all.

“Running in environments with different distracting features may adversely affect running performance and injury risk,” explains Herman. “Sometimes these things cannot be helped, but you may be able to minimize potentially cumulative effects. For example, when running a new route in a chaotic environment such as during a destination marathon, you may want to skip listening to something which may require more attention – like a new song playlist or a podcast.”

Herman’s team will continue to investigate the potential relationship between distracted running and leg injuries, including the characteristics of runners who may be more or less susceptible to this effect, and any effect this relationship has on different training techniques that use auditory or visual cues.