- A great research article in Mayo Clinic Proceedings, marked below, demonstrates the importance of decreasing our sedentary activities. In the study, they determined that telomere length is shortened by sedentary behaviors, measured in the form of leisure-based screen time. Short telomeres is associated with stress, inflammation, and a variety of cardiometabolic diseases! Short telomeres are an established characteristic of aging. You want to have a successful aging strategy, hence you want to keep your telomeres long! 🙂
- The measurement of leukocyte telomere length (LTL) is a method to determine future health, and short LTL is associated with morbidity and mortality independent of age. In the study, 6405 people ages 20-84 were assessed for leisure time screen-based sedentary behavior, namely television, video games and computer use, and a LTL assay was performed on the participants to determine the length of their telomeres over a certain period of time. It was found that for every hour increase in screen based time, the individual had a 7% increased risk of being in the lowest tertile of telomere length. In other words, the more screen based time that was spent, the greater the chance your telomeres were short enough to put you at the bottom of the study group in regards to telomere length. Hence you have a higher risk of an early illness or death!
- Physical activity is associated with greater telomere length up to a certain point.
- The core findings of people with LTL values that were in the bottom group (short telomeres) was that they were more sedentary, engaged in little moderate to vigorous physical activity, had high CRP levels (inflammation marker), had a higher BMI (fatter), and more likely to have diabetes, hypertension, and coronary artery disease. The chance of a person falling into this category, again increased by 7% for each hour of screen based leisure time that they spent.
- Leukocyte telomere shortening is a marker of cellular aging and also is associated with increased morbidity (high blood pressure/diabetes) and mortality. When LTL become critically shortened, the leukocytes secrete pro-inflammatory cytokines and hence increase the CRP ( a marker of inflammation). Thus being sedentary results in inflammation and modulates your metabolic risk in the wrong direction. In other words, you age faster!!!
- The key point: Stay active physically and spend less time on Facebook!!
- Leisure-Time Screen-Based Sedentary Behavior and Leukocyte Telomere Length: Implications for a New Leisure-Time Screen-Based Sedentary Behavior Mechanism – Paul Loprinzi
Other interesting abstracts:
Bey, L. and Hamilton, M.T. Suppression of skeletal muscle lipoprotein lipase activity during physical inactivity: a molecular reason to maintain daily low-intensity activity. J Physiol. 2003; 551: 673–682
Suppression of skeletal muscle lipoprotein lipase activity during physical inactivity: a molecular reason to maintain daily low-intensity activity Bottom line of article: Inactivity caused a local reduction of plasma [3H]triglyceride uptake into muscle and a decrease in high density lipoprotein cholesterol concentration. Treadmill walking raised LPL activity approximately 8-fold (P < 0.01) within 4 h after inactivity The striking sensitivity of muscle LPL to inactivity and low-intensity contractile activity may provide one piece of the puzzle for why inactivity is a risk factor for metabolic diseases and why even non-vigorous activity provides marked protection against disorders involving poor lipid metabolism.
Tremblay, M.S., Colley, R.C., Saunders, T.J., Healy, G.N., and Owen, N. Physiological and health implications of a sedentary lifestyle. Appl Physiol Nutr Metab. 2010; 35: 725–740 Sedentarism, active lifestyle and sport: impact on health and obesity prevention
The benefits of regular physical activity have been known since ancient Greek. But in the last Century the scientific knowledge around this topic has progressed enormously, starting with the early studies of JN Morris and RS Paffenberger, who demonstrated that physical activity at work reduced incidence of cardiovascular disease and mortality. In the Harvard alumni study, the lowest risk was associated with a weekly output of 1000 to 2000 kcal performing vigorous activities. Further studies in all age groups have supported these findings and have added that even moderate levels of physical activity provide considerable benefits to health, including lower prevalence of overweight and obesity at all ages. Metabolic fat oxidation rate is highest at exercise intensities between 45 and 65% of VO2max. This means that people must be active regularly and force physiological mechanisms at certain intensities. All this body of evidence has contributed to current WHO physical activity recommendations of 150 min/week of moderate to vigorous physical activity (MVPA) in adults and elderly, and 60 min/day of MVPA in children and adolescents, with additional strength training, apart from adopting an active lifestyle. In the last 50 years, occupational physical activity has been reduced for about 120 kcal/day, and sedentarism has emerged as an additional risk factor to physical inactivity. Even if less than 60 min of TV time in adults have been related to lower average BMI, there is still a need for research to determine the appropriate dose of exercise in combination with sedentary behaviours and other activities in the context of our modern lifestyle in order to prevent obesity at all ages. As public health measures have failed to stop the obesity epidemic in the last 3 decades, there is clearly a need to change the paradigm. The inclusion of sport scientists, physical education teachers and other professionals in the multidisciplinary team which should be responsible for drawing the road map to prevent the increase of the obesity epidemic effectively is a “must” from our point of view.
Bergouignan, A., Rudwill, F., Simon, C., and Blanc, S. Physical inactivity as the culprit of metabolic inflexibility: evidence from bed-rest studies. J Appl Physiol (1985). 2011; 111: 1201–1210
PHYSICAL INACTIVITY INDUCES INSULIN RESISTANCE. PHYSICAL INACTIVITY DECREASES FAT OXIDATION. PHYSICAL INACTIVITY AFFECTS LIPID TRAFFICKING BETWEEN ADIPOSE TISSUE AND MUSCLE. PHYSICAL INACTIVITY INDUCES ECTOPIC FAT STORAGE. OVERALL, THE PHYSICAL ACTIVITY LEVEL PREDICTS METABOLIC FLEXIBILITY.
The following sequence of events can be hypothesized to explain the physical inactivity-induced metabolic alterations and thus metabolic inflexibility (Fig. 4). The physical inactivity induced by bed rest leads to insulin resistance in skeletal muscle, requiring a hyperinsulinemic response to properly dispose of glucose in daily postprandial conditions, whereas adipose tissue displays an appropriate response. At the same time, muscle fiber type shifts toward fast-twitch glycolytic fibers, and muscle increases glucose uptake and oxidation through insulin-independent pathways. This in turn inhibits fatty acid oxidation and ultimately uptake. During meal ingestion, hyperlipemia occurs due to a decreased plasma clearance of dietary fat. This increases the flux of dietary lipids to organs and results in ectopic fat storage with consequences on insulin sensitivity. The liver displays susceptibility to hyperinsulinemia and increased lipid synthesis and storage that overcomes rate of oxidations. Hepatic steatosis will likely ensue. With a reduced oxidative capacity, the liver will then contribute to an increased rate of atherogenic lipid products (VLDL) in which the contributions of FFA coming from the diet and neolipogenesis to the total VLDL-triglycerides will increase, feed-forwarding hyperlipemia and ectopic fat storage. Concomitantly, the steatotic liver will become insulin resistant and unable to suppress hepatic glucose production, which leads to increased gluconeogenesis and feed-forward worsening of hyperinsulinemia.Hypothetical metabolic alterations cascade induced by bed rest that can explain how physical inactivity induces metabolic inflexibility. VLDL, very-low-density lipoprotein; NAFLD, nonalcoholic fatty liver disease; DAG, diacylglycerol.
Physical activity predicts metabolic flexibility. For an equivalent food quotient, metabolically flexible subjects will greatly increase carbohydrate oxidation after the consumption of a meal despite a low increase in plasma insulin concentration. A metabolically inflexible individual, i.e., a person who also displays an insulin resistance, will display a low increase in carbohydrate oxidation despite an marked elevation in insulin secretion.
Weischer, M., Bojesen, S.E., Cawthon, R.M., Freiberg, J.J., Tybjӕrg-Hansen, A., and Nordestgaard, B.G. Short telomere length, myocardial infarction, ischemic heart disease, and early death. Arterioscler Thromb Vasc Biol.2012; 32: 822–829
Short Telomere Length, Myocardial Infarction, Ischemic Heart Disease, and Early Death -> Findings: Short telomere length is associated with only modestly increased risk of myocardial infarction, ischemic heart disease, and early death.
Leucocyte telomere length and risk of cardiovascular disease: systematic review and meta-analysis BMJ 2014;349:g4227 Available observational data show an inverse association between leucocyte telomere length and risk of coronary heart disease independent of conventional vascular risk factors. The association with cerebrovascular disease is less certain.
Chronic inflammation induces telomere dysfunction and accelerates ageing in mice Our results show that chronic inflammation aggravates telomere dysfunction and cell senescence, decreases regenerative potential in multiple tissues and accelerates ageing of mice. Anti-inflammatory or antioxidant treatment, specifically COX-2 inhibition, rescued telomere dysfunction, cell senescence and tissue regenerative potential, indicating that chronic inflammation may accelerate ageing at least partially in a cell-autonomous manner via COX-2-dependent hyper-production of ROS.
Cawthon, R.M. Telomere measurement by quantitative PCR. Nucleic Acids Res. 2002; 30: e47 Telomere measurement by quantitative PCR