The Met-Ex study started up in 2012. The aim is to examine whether high intensity interval training (HIT) yields greater beneficial effects on risk factors for metabolic syndrome than continuous moderate intensity exercise (CME). The study is designed with a 16-week exercise program and one and three year follow up. In addition, the importance of the volume of aerobic interval training remains unclear. It is unknown how little “one can get away with” and still gain beneficial cardiovascular effects. Therefore, we also want to determine whether 1×4 minutes of aerobic interval training at high intensity can confer beneficial effects compared to 4×4 minutes with high intensity and continuously moderate intensity exercise.
As a fan of high contact sports the last few weeks have made for some exciting viewing for me. American football’s flagship event, Superbowl XLVIII on Feb 2nd, saw the Seattle Seahawks overwhelm a hapless Denver Broncos 43-8, amazingly not the worst margin of defeat in the Broncos somewhat unfortunate Superbowl history. That same weekend also saw the start of the 2014 Six Nations, the biggest international rugby union tournament in the northern hemisphere. It was with a sad heart then that my enthusiasm the following Monday morning was met with the baffled looks and shrugged shoulders of my work colleagues. And then a realization hit me; since I had moved to Norway one year previously, I hadn’t met a single person who actually played either sport.
A quick Google search was able to lower my initial fears somewhat when I found that professional organizations exist in Norway for both American football (Norges Amerikanske Idrettsforbund) and rugby union (Norges Rugbyforbund). Following for the two sports appears to be gathering momentum, but both are still in relative infancy. The NAIF website itself acknowledges that while American football is growing in Norway, it is still not a widespread sport. I find myself asking why. Alongside the Netherlands, Sweden and Denmark, Norway is one of the tallest nations in the world. This innate physicality almost certainly lends itself well to the popularity of ice hockey in Scandinavia. High impact sports certainly have a great deal to offer individuals in terms of physical fitness.
The origins of American football rules are heavily steeped in versions of rugby played during the 19th century and as such similarities between the two are evident even today. The objective of both sports is to carry the ball, a prolate spheroid rather than the traditional spherical ‘football’, deep into the opponents half of the field. Scoring can occur in each by carrying the ball over the goal line or, under certain special conditions, kicking the ball between the tall upright goalposts located on each goal line.
The differences between the two arise from the style of play and length of the game. Rugby has more of a focus on open play, with stoppages generally only occurring when the ball leaves the field of play or a foul is committed. American football however focuses on short bursts of intense play, where the attacking team attempts to gain a relatively small amount of ground within 4 attempts, known as ‘downs’. In rugby the ball can be kicked forward, but may only be passed to the side or backwards, whereas in American football the ball can be thrown forward during a period of play, usually by a specialist known as the quarterback. Such plays generally gain more ground than a simple run of the ball at the opposing team.
A key ingredient is the emphasis on physicality and strength as well as speed. Like other team sports, there are specialized positions which mean that not everyone can play in any position during a game. The fundamental difference in these high collision sports is that specialization also involves particular size, strength and body shape characteristics. Consequently, playing individuals that don’t meet these criteria within those specialized positions is not only disadvantageous to a team, it can also be extremely dangerous. The increase in sporting professionalism in recent decades has radically altered the landscape of high collision sports such as American football and rugby. Stricter training and dietary regimes have led to an explosion in the size and strength of elite players. Current training strategies in these sports involve a mixture of high intensity interval and strength training, giving participants the best of both worlds in terms of fitness benefits.
Current size demands at the elite level may bring with them the potential for an increased strain on the body, in particular the cardiovascular system. Last year Steffes et al reported that metabolic syndrome, which describes an individual’s risk for metabolic or cardiovascular disease, was present at a similar rate in high school and college football players when compared to aged-matched general populations, however over 90% of the positive cases of metabolic syndrome were limited to offensive and defensive linemen who exhibited higher percentage body fat. In linemen, an elevated heart mass when adjusted for body size has also been reported by Uberoi et al. (2013). Karpinos et al. (2013) investigated the prevalence of hypertension (high blood pressure) between football and non-football playing American college athletes, and found that rates were approximately 10% higher in football players. Given this evidence it is likely that in American football, particularly for linemen, coaches and trainers should pay particular attention to athletes training regimes and monitor cardiovascular health closely.
While mass is a critical factor in elite athletes, those looking for a physical challenge at an amateur level will definitely find a place in either sport regardless of their size and fitness level. The emphasis on explosive speed and strength in American football and rugby means that both offer a fantastic physical workout simply during training, even outside a full game situation. So hang up those skates Norway, put on your helmet and pads, or your scrum cap, and get out onto that field.
Allen Kelly, Post Doc at CERG
Overweight, obesity and inactivity are emerging as a pandemic and are major risk factors for type-2 diabetes and cardiovascular disease (CVD). According to World Health Organization the prevalence of obesity in Europe has tripled in the last two decades, and in line with this, the latest figures from the Health Survey of Nord-Trøndelag (HUNT) show that 60 % of the population can be classified as overweight. Of those, 20 % can be classified as obese. The proportion of obese men in Norway has tripled in the recent 20 years and the incidence of type-2 diabetes has consequently increased. This is expected to result in increased incidence of CVD in the general population.
Additionally, an excessively high level of lipids in your blood (hyperlipidemia) can also have an effect on your health. High cholesterol itself does not cause any symptoms, but it increases your risk of serious health conditions. Alltogether, this and similar risk factors are called metabolic syndrome. Therapeutic lifestyle changes, including exercise, are the first line of treatment for patients with the metabolic syndrome. The health benefits of exercise have been exhaustively studied by our group, and the most notable of which is an increase in cardiorespiratory fitness. Importantly, cardiorespiratory fitness has been identified as the strongest independent predictor of both all cause and cardiovascular disease mortality in nearly every population in which it has been examined. Large-scale epidemiological studies demonstrate that aerobic fitness is the single best predictor for future cardiovascular mortality in healthy individuals and in patients with cardiovascular disease.
But, when lifestyle changes (such as exercise or diet) fail to achieve cholesterol reduction in patients with the metabolic syndrome or those with multiple cardiovascular disease risk factors (diabetes, obesity, high blood pressure, etc), medicines to lower cholesterol are prescribed to reduce the risk of coronary heart disease morbidity and mortality. Indeed, statins are the most widely prescribed drug around the world and can lower your cholesterol.
However, a scientific paper published this month in the Journal of the American College of Cardiology examined the effects of statin treatment on changes in cardiorespiratory fitness induced by exercise and shows some interesting results. Obese volunteers performed a supervised exercise training program: 45 minutes of treadmill walking or jogging at 60-75 % of heart rate reserve, 5 days per week for a total period of 12 weeks or the combination of exercise and simvastatin. The results actually showed that statins attenuated the benefits of exercise in the cardiorespiratory fitness when combined with exercise training in overweight or obese patients at risk of the metabolic syndrome.
Interestingly, statins also seem to be poorly tolerated among elite athletes. Another scientific study published few years ago monitored 22 professional athletes through 8 years in whom, because of familial hypercholesterolemia, treatment with different statins was attempted. These findings indicated that in top sports performers, only 2 of 10 tolerated statin treatment without side-effects. Among others, the medicine increased the susceptibility to muscle damage during exercise.
It is no doubt that statins lower too high cholesterol levels, but as observed, it may have negative side effects as well. Our recommendation is rather to try exercise first – it is free, gives energy and has no side effects.