That wast the question we asked high school students during Researcher’s Night at the Science building, Gløshaugen at NTNU last Friday. This is an event held during the Science Days, an annual festival where various research institutes are invited to showcase their work. Before the weekend, hundreds of high school students attended this event to meet researchers at various stands. There was everything from flying drones to the three of us from CERG with a stationary bike and equipment for measuring maximal oxygen uptake (VO2max). Continue reading
Researchers in our group have found that current physical activity guidelines for health are insufficient to mitigate long-term weight gain. The study was published in British Journal of Sports Medicine, and are based on data from The HUNT study i Norway.
The current guidelines for physical activity for health benefits say that all adults should do moderate-intensity activity a minimum of 150 minutes, or vigorous-intensity activity for 60 minutes or more, each week. But do this level of physical activity prevent long-term weight gain?
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?
Here in Norway, we have four beautiful seasons. We are finishing one of the finest summers in modern time, and now the autumn is knocking heavily on our doors. Following the change of season also comes a colder weather, and shortened time of sunlight during the day. Importantly, also comes increased incidence of bad colds, fever and different airway infections. Some swear to vitamins, honey, and a number of other nutrients and experimental ways of avoiding these unpleasant, but usually mild and harmless diseases. However, have you taken your daily dose of exercise as medicine?
In the last 20 years there have been more and more evidence that small to moderate amounts of red wine have a protective effect on cardiovascular disease. Several reasons have been discussed, such as the wine’s antioxidant properties and its ability to expand blood vessels. Several studies have also shown that wine increases levels of HDL, the “good” cholesterol.
During the annual Heart Congress in Barcelona came the startling news of a major Czech study showing that wine only protects against cardiovascular disease in people who exercise.
It is well established that aerobic exercise training causes reduction in the resting heart rate. This has traditionally been associated with autonomic signals from the nervous system. A new study recently published in Nature Communications challenges this view by demonstrating that reduction in resting heart rate is a result of training-induced changes in the heart itself, specifically, changes in the heart’s natural pacemaker, the sinus node.
In this study which is performed by CERG, NTNU, The University of Manchester and The University in Milano, the researchers showed in rodent models of endurance training that even the absence of stimulation from the autonomous nervous system, a reduced resting heart rate was still present. This result led to further investigation of mechanisms underlying training induced reduction in resting heart rate. The researchers demonstrated that the heart’s pacemaker changes in response to training and in particular there is a downregulation of an important protein known as the funny channel (or HCN4) which is responsible for controlling the rhythm of the sinus node and thereby responsible for the low heart rate.
Article about the study in BBC News: Endurance exercise interferes with heart rythm.
Athletes are considered the healthiest members of the society and aerobic exercise training is undoubtedly beneficial for the heart. However, elderly athletes with a lifelong history of training and competing in endurance events such as cross country skiing and marathons are prone to heart rhythm disturbances. The most frequent rhythm disturbance in response to exercise training is reduced resting heart rate, less than 50-60 beats per min. While normal adults have resting heart rates between 60-100 beats per min, it has been reported resting heart rates as low as 30 beats per min in elite endurance athletes, for example Bjørn Dæhlie had a heart rate of about 30 beats per min. Low heart rate in athletes is usually a benign physiological adaptation in the heart, however, it can cause problems especially in elderly athletes with a lifelong training history and veteran athletes are more likely to need an electronic pacemaker implantation (to keep the heart in regular rhythm).
Although exercise training is beneficial, intense endurance training can have harmful effects and in the referred study the authors have highlighted potential pathological remodeling in the sinus node. The volume and intensity of exercise training may be of critical importance for remodeling in the heart and identification of harmful training induced changes in the heart may lead to changes in training regimes to avoid such changes. In addition it may suggest potential therapeutic targets for veteran athletes which are prone to heart rhythm disturbances.
The positive effects exercise training has on the heart, more than outweigh the harmful once. So keep on exercising!
Anne Berit Johnsen, researcher at CERG
For å oppnå en ytterligere helsegevinst er det spesifisert at voksne bør øke moderat fysisk aktivitet inntil 300 minutt per uke eller høy intensitet inntil 150 minutt per uke, eller en kombinasjon av moderat og høy intensitet. Barn og ungdom anbefales minst 60 minutt hver dag med fysisk aktivitet av moderat og høy intensitet. Minst tre ganger i uken bør aktiviteter med høy intensitet som gir økt muskelstyrke og styrker skjelettet, inkluderes.
Både moderat fysisk aktivitet og trening med høy intensitet har positiv virkning på helsen, men forskning viser at aktivitet med høy intensitet gir en mer robust reduksjon av risiko for å utvikle blant annet hjerte- og karsykdommer og type 2 diabetes.
Andrea Hegdahl Tiltnes, CERG
The last decade has seen an opposite trend to advice people how much body weight they need to have for longer survival. This includes reports that suggest that few extra kilos than normal body mass index (BMI) is helpful. In contrary, long standing evidence has shown that having a normal BMI is more favorable for cardiovascular health.
In a previous blog piece, we have briefly discuss the evidence associated with being over-weight, and how these extra few kilos maybe beneficial for overall health.
However, in a recent investigation that involves 1.9 million participants, overweight and obesity were associated with increased risk of coronary heart disease and stroke. In this pooled analysis of 97 prospective cohorts, each 5 kg/m2 higher BMI was associated with 27% increase risk of death from coronary heart disease, and 18% increased risk of death from stroke. The positive association of BMI and increased risk of death was mediated by other metabolic risk factors (blood pressure, cholesterol, and glucose). However, ever after adjustment of these three metabolic factors, the risk of death from coronary heart disease was 15% higher, and that of stroke was 4% higher. In line with this, being overweight was associated with 26% increased risk of coronary heart disease, and 13% increased risk of stroke death when compared with normal weight. While obesity had a larger association: 69% increased risk of death from coronary heart disease, and 47% increased risk of stroke. The jury is out there to decide whether to maintain an optimum body weight or few extra kilos of body weight are desirable.
Meanwhile, overwhelming evidence has suggested that maintaining a normal weight (BMI, 18 to 25 kg/m2) is much favorable for a better cardiovascular risk profile, and a longer survival. On the other hand, being physically active not only helps to keep your body weight in control, but also beneficial for a lot other things, including lowering of blood pressure, total cholesterol and a better cardiac health. So far, a balanced lifestyle that includes smoking cessation, physical activity, and healthy diet among others would be advisable to people in all ages and in both sexes.
Javaid Neuman, Researcher CERG
There remains little doubt that lack of exercise and a sedentary lifestyle represent key health problems in today’s modern society. A quick search on the World Health Organisation’s (WHO) website and you’ll find that physical inactivity ranks 4th in the global leading risk factors for mortality, with many countries around the world demonstrating a trend for women to be less active than men. While health organisations around the world are making a concerted effort to encourage the general public to incorporate exercise into their leisure and free time, this may not be the only period of our day that is dominated by sedentary behavior. Work forms one of the largest segments of sedentary time for employed individuals, and current trends have shifted parts of the working population into less active, ‘sitting’ jobs.
But what does this mean for our long-term health? One study, published last month in PLoS ONE, aimed to answer this question by assessing the impact of occupational sitting on the risk of cancer, cardiovascular disease, and all-cause mortality from a large number of British men and women. Stamatakis and colleagues gathered data from identical health surveys conducted in England and Scotland between 1994 and 2004. Subjects (5380 women, 5788 men) were classified based on whether the majority of time in their job was spent walking, standing or sitting. Subjects were further categorized on levels of physical activity during free time, alcohol intake, smoking, socioeconomic status, and whether they had cardiovascular disease or cancer at the time of the survey. The mortality rate (number of deaths) was then monitored over a 13 year follow-up period.
The major findings reported by this study were that standing/walking occupations carried a lower risk of mortality from either all-causes or cancer, in women but not men. When the researchers further compared groups based on free-time physical activity levels, they found that in both men and women, high levels of free-time physical activity coupled with a standing/walking occupation was associated with a lower risk of cancer and all-cause mortality versus low free-time activity coupled with sitting occupation. At first glance, it could be easy to take the results at face value, but there are limitations to the study design which the authors themselves highlight: Much of the data is self-reported, which may introduce bias, especially when it comes to levels of physical activity during free-time. In addition, there was no information available on how long individuals had been in their current jobs, nor was there any data for people switching jobs during the 13 year follow-up, which may have eventually placed them into a different category. The findings are also surprising given that a similar study published earlier in the year, found that even moderate free-time exercise was enough to reduce the risk of both cardiovascular and all-cause mortality, regardless of levels of physical activity in work.
The issue still seems unresolved, and it has also been discussed here on the blog earlier. Current exercise recommendations from the Norwegian Directorate of Health suggest daily physical activity levels should be at least 30 min, a total 3.5 hours per week, which has been shown in a number of studies to confer significant benefits to health and an overall decrease in mortality rates. However, a busy lifestyle, coupled with raising a family may make this target difficult to reach during our leisure time, making activity levels at work a significant factor in overall health. Everything is better than nothing, and maintaining a physically active lifestyle outside of work hours will contribute significantly to achieve the health benefits of exercise. However, if you’re still worried and have been sat at your desk for the last few hours, when you reach the end of this sentence, why not stand up and take a walk?
Allen Kelly, post doc at CERG.
I de siste tiårene har vi hatt en massiv vekst av kjøttforbruk i Norge, og i følge en rapport fra Helsedirektoratet, har vi gått fra å spise omtrent 50 kg kjøtt per person i 1980 til nesten 80 kg i 2010. Denne enorme veksten har sannsynligvis store effekter på helse og miljø. For å forsøke å bremse økningen i kjøttforbruk og forbedre folkehelsa oppfordrer helseeksperter til å spise vegetarisk mat minst en dag i uka. Konseptet «Meatfree Monday», ble opprinnelig lansert i USA for å forbedre forbrukernes helse, men har spredt seg til flere steder i Europa og resten av verden.
Dessverre henger Norge noe etter når det gjelder utvalg av vegetariske matvarer i butikkene og på restauranter i forhold til mange andre land i verden. Heldigvis er dette noe politikerne nå ser ut til å ta tak i. Tidligere i høst vedtok Oslo bystyre at det skal legges til rette for valgmuligheter mellom kjøtt/fisk og vegetarmat i kommunens kantiner. Her følger noen gode grunner for å innføre «Meatfree Monday» også i din familie:
Helse: Det økte kjøttforbruket gjør at nordmenn får i seg for mye mettet fett. Flere studier viser at et kosthold uten eller med små mengder rødt kjøtt minker risikoen for hjerte- og karsykdommer og type-2 diabetes. Personer som spiser lite kjøtt har også lavere BMI og blodtrykk. Sammenhengen mellom kjøttinntak og kreft er ikke like godt bevist, men flere studier tyder på at mindre inntak av kjøtt kan redusere risiko for tarmkreft og brystkreft.
Miljø: Produksjon av kjøtt og andre animalske produkter står, ifølge Framtiden i Våre Hender, for omkring 18 prosent av de samlede klimagassutslippene og bidrar mer til den globale oppvarmingen enn hele transportsektoren. Beregninger antyder at hvis alle husstander i Norge hadde spist kun 1 pakke kjøttdeig mindre i måneden, ville det spart miljøet for CO2-utslipp tilsvarende det årlige utslippet fra omtrent 60 000 privatbiler.
Så med dette vil jeg anbefale alle sammen å innføre Meatfree Monday og i tillegg huske å invitere gode venner på vegetarmiddag i jula.