High fitness reduces risk of atrial fibrillation

Two women running outdoorOverweight, hypertension, diabetes and sleep apnea increases the risk of developing atrial fibrillation (AF). Interventions aimed at these risk factors are known to reduce the risk and improve the outcome for most cardiovascular diseases. However, there has been lacking knowledge on the effect of such interventions on AF, and there has been considerable attention on the finding that large amounts of endurance exercise increases the risk of developing AF. Recent years, there have been published some studies examining this topic.

Read also: CERG at ESC 2014

Continue reading

Exercise in prevention of metabolic syndrome

Blotrykksmåling av pasien i studien metExThe 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.

Continue reading

High intensity interval training reduces risk of cardiovascular diseases in elderly and obese

Kondisjonstrening (Illustrasjonsfoto: Geir Mogen)Les dette blogginnlegget på norsk her!

Noncommunicable diseases (NCDs) are now the leading cause of death and disability worldwide, with cardiovascular diseases being the number one cause. Because of the recent changes in world demographics with an increasing number of elderly and obese, NCDs are expected to increase in the years to come. Physical inactivity is one of the most important risk factors for cardiovascular disease, and aerobic exercise training is shown to improve both aerobic capacity and endothelial function, two important and strong prognostic factors for cardiovascular mortality. However, little is known about the effects of high intensity exercise on cardiovascular risk factors in elderly and obese subjects.

Continue reading

Keeping it up! Do people continue to exercise after discharge from cardiac rehabilitation?

Kondisjonstrening (Illustrasjonsfoto: Geir Mogen)Les dette innlegget på norsk her!

It has been shown that a rehabilitation program that includes exercise training reduces mortality in subjects with coronary heart disease. To have a high cardiorespiratory fitness, that is a high maximum oxygen uptake (VO2max), is strongly predicting survival in these subjects – as well as in the rest of us.1 Therefore, it is smart to find out how to increase the VO2max effectively by exercise training.

In CERG, we have done several studies showing that high intensity interval training (HIT) give larger improvements in VO2max compared to moderate continuous exercise.2,3 Our training studies typically last for three or four months, with a lot of supervision and good patient compliance. But is HIT something people can do on a regular basis during the rest of their life?

Continue reading

When every percent counts – new CERG publication

High-intensity exercise is shown to be protective against coronary heart disease (CHD) and is established as a popular and time saving exercise method. But what about people who already have a heart disease? Earlier, these patients were told to exercise, but only with moderate intensity to protect the heart from further damage. However, during the last few years it has been found that high-intensity exercise does not represent a greater risk of adverse events in these patients – on the contrary, this type of exercise is very beneficial even for this patient group.

Several studies comparing high intensity interval training with moderate exercise have found greater effect of higher intensity. But high do you have to go during the intervals? What are the characteristics of the “ideal” interval training session? This was the main question of a new study from Moholdt and colleagues from CERG, in this months Journal of Science and Medicine in Sport. In order to identify the most important predictor of improved fitness in CHD patients, the researchers analyzed data from four randomized, controlled trials conducted at the center. The main outcome was change in VO2max, peak oxygen uptake, which is a well-established measure of fitness and predictor of mortality. Subjects (n=112) were aged 18+ and had established CHD. The exercise period lasted for 12 weeks, and exercise was performed by either running/walking on treadmill, uphill walking outdoors or group training, after the 4×4 model.

CERG researcher Trine Moholdt during testing.

CERG researcher Trine Moholdt during testing.

Interestingly, when baseline and post-training VO2max was compared, the researchers found that the amount of training sessions had no impact on fitness, neither had the age of the subjects or baseline peak oxygen uptake. On the other hand, the intensity of training played a key role in improving VO2max and seems to be the most important characteristic of an effective interval session.

The traditional advice in interval training is that in the intensive periods, heart rate should be 85-95% of HRmax. However, this range is rather wide, and this study suggests that it is not indifferent where in the range you place yourself. Overall, VO2max increased by 11.9 % after an average of 23.4 training sessions during the 12 week period for all subjects. But, an intensity of >92 % of HRmax in the high-intensity periods was shown to be more effective than lower intensity (e.g. 85-88%), indicating that there is a dose-response relationship even within the HR zone of 85-95%.

It may seem like minor details, but people who start exercising intervals often have lots of questions on how to do it practically. How much incline on the treadmill? Can I short down to 2 calm minutes in-between the 4 minutes of high intensity? Why 4 minutes and not 5? Knowing that pushing oneself up to >90 % of HRmax may save you from an extra training session with lower intensity that week, gives meaning to the process of investigating even minimal details.

The four studies included patients with established CHD, either presented as acute coronary syndrome or angina pectoris. However, it is reasonable to believe that even small adjustments in intensity may be efficient also for healthy persons. So why don’t you push yourself the last 2-3 percents when you are exercising anyway?

Maria Henningsen, CERG