Anders Karlsen

Life-long endurance exercise in humans: Circulating levels of inflammatory markers and leg muscle size

Human aging is associated with a loss of skeletal muscle and an increase in circulating inflammatory markers. It is unknown whether endurance training (Tr) can prevent these changes. Therefore we studied 15 old trained (O-Tr) healthy males and, for comparison, 12 old untrained (O-Un), 10 Young-Tr (Y-Tr) and 12 Young-Un (Y-Un). Quadriceps size, VO2 peak, CRP, IL-6, TNF-α and its receptors, suPAR, lipid profile, leucocytes and glucose homeostasis were measured. Tr was associated with an improved insulin profile (p<0.05), and lower leucocyte (p<0.05) and triglyceride levels (p<0.05), independent of age. Aging was associated with poorer glucose control (p<0.05), independent of training. The age-related changes in waist circumference, VO2 peak, cholesterol, LDL, leg muscle size, CRP and IL-6 were counteracted by physical activity (p<0.05). A significant increase in suPAR with age was observed (p<0.05). Most importantly, life-long endurance exercise was associated with a lower level of the inflammatory markers CRP and IL-6 (p<0.05), and with a greater thigh muscle area (p<0.05), compared to age-matched untrained counterparts. These findings in a limited group of individuals suggest that regular physical endurance activity may play a role in reducing some markers of systemic inflammation, even within the normal range, and in maintaining muscle mass with aging.

Effect of Heat and Heat Acclimatization on Cycling Time Trial Performance and Pacing

ABSTRACT Purpose This study aimed to determine the effects of heat acclimatization on performance and pacing during outdoor cycling time trials (TT, 43.4 km) in the heat. Methods Nine cyclists performed three TT in hot ambient conditions (TTH, approximately 37°C) on the first (TTH-1), sixth (TTH-2), and 14th (TTH-3) days of training in the heat. Data were compared with the average of two TT in cool condition (approximately 8°C) performed before and after heat acclimatization (TTC). Results TTH-1 (77 ± 6 min) was slower (P = 0.001) than TTH-2 (69 ± 5 min), and both were slower (P < 0.01) than TTC and TTH-3 (66 ± 3 and 66 ± 4 min, respectively), without differences between TTC and TTH-3 (P > 0.05). The cyclists initiated the first 20% of all TT at a similar power output, irrespective of climate and acclimatization status; however, during TTH-1, they subsequently had a marked decrease in power output, which was partly attenuated after 6 d of acclimatization and was further reduced after 14 d. HR was higher during the first 20% of TTH-1 than that in the other TT (P < 0.05), but there were no differences between conditions from 30% onward. Final rectal temperature was similar in all TTH (40.2°C ± 0.4°C, P = 1.000) and higher than that in TTC (38.5°C ± 0.6°C, P < 0.001). Conclusions After 2 wk of acclimatization, trained cyclists are capable of completing a prolonged TT in a similar time in the heat compared with cool conditions, whereas in the unacclimatized state, they experienced a marked decrease in power output during the TTH.

Differential satellite cell density of type I and II fibres with lifelong endurance running in old men.

To investigate the influence of lifelong endurance running on the satellite cell pool of type I and type II fibres in healthy human skeletal muscle.

Matters of fiber size and myonuclear domain: Does size matter more than age?

Introduction: The relationship between fiber size and myonuclear content is poorly understood. Methods: Biopsy cross‐sections from young and old trained and untrained healthy individuals were analyzed for fiber area and myonuclei, and 2 fiber‐size‐dependent cluster analyses were performed. Results: When comparing fibers of similar size, no effect of training or age was found for myonuclear domain. There was a linear relationship between fiber area and myonuclei per fiber (r = 0.99; P < 0.001) and a non‐linear relationship between fiber area and domain (r = 0.97–0.99; P < 0.0001), with a markedly smaller domain in fibers <3,000 µm2. A higher proportion of type II fibers <3,000 µm2 was observed in the old subjects. Conclusions: These findings suggest that age‐related reductions in myonuclear domain size could be explained by the greater proportion of small fibers. The data also highlight the usefulness of determining fiber‐size‐based clusters for gaining mechanistic insight into the relationship between skeletal muscle fiber size and myonuclear content. Muscle Nerve 52: 1040–1046, 2015

Improved Functional Performance in Geriatric Patients During Hospital Stay.

Objective The aim of this work was to evaluate the time course of changes in strength and functional performance in elderly hospitalized medical patients. Design This was a prospective observational study in elderly medical patients of age 65 years or older at a geriatric department. Measurements were obtained on days 2 to 4, day 5 to 8, and days 9 to 13. Functional performance was measured with De Morton Mobility Index (DEMMI) test and a 30-second chair stand test (30-s CST). Muscular strength was measured with handgrip strength. Activity level was determined with accelerometry (ActivPAL). Results Results in DEMMI and 30-s CST gradually improved (P < 0.05), whereas handgrip strength remained unchanged (P > 0.05). Larger functional improvements were observed in patients with “high” compared to “low” and “moderate” activity level (P < 0.05). Changes in DEMMI score correlated with changes in 30-s CST (P < 0.05); however, changes in DEMMI score and 30-s CST were more likely to occur in patients with a low versus high functional level, respectively. Conclusions Functional performance of the lower extremities in geriatric patients improves moderately over the time of a hospital stay of less than 14 days, with larger improvements in patients with high activity level. The DEMMI test and the 30-s CST seem to be complementary to each other when evaluating functional changes in a geriatric hospital population. To Claim CME Credits Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME Objectives Upon completion of this article, the reader should be able to (1) describe changes in mobility and muscle strength of geriatric patients during a hospital stay of less than 14 days, (2) understand the significance of physical activity during hospital admission in geriatric patients, and (3) discuss the potential limitations of measures for assessing mobility and lower extremity strength status and change during a hospital admission. Level Advanced Accreditation The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Skeletal muscle morphology and regulatory signalling in endurance-trained and sedentary individuals: The influence of ageing

ABSTRACT Muscle mass in humans is inversely associated with circulating levels of inflammatory cytokines, but the interaction between ageing and training on muscle composition and the intra‐muscular signalling behind inflammation and contractile protein synthesis and degradation is unknown. We studied 15 healthy life‐long endurance runners, 12 age‐matched untrained controls, 10 young trained and 12 young untrained individuals. Thigh muscle composition was investigated by magnetic resonance imaging (MRI), where non‐contractile intramuscular tissue (NCIT) area (fat and connective tissue) was found to be greater in older but lower in trained individuals. Subcutaneous adipose tissue was also lower in trained individuals but was not affected by age. In vastus lateralis biopsies, no influence of age or training was found on levels of endomysial collagen, determined by Sirius Red and Collagen III staining, whereas perimysial organisation tended to be more complex in older individuals. No clear difference with training was seen on intramuscular inflammatory signalling, whereas lower protein levels of NFkB subunits p105, p50 and p65 were observed with ageing. Gene expression of IL6 and TNF&agr; was not different between groups, while IL1‐receptor and TNF&agr;‐receptor1 levels were lower with age. Myostatin mRNA was lower in older and trained groups, while expression of MuRF1 was lower in trained individuals and FoxO3 expression was greater in aged groups. The association of increased muscle NCIT with age‐associated muscle loss in humans is not accompanied by any major alterations in intramuscular signalling for inflammation, but rather by direct regulatory factors for protein synthesis and proteolysis in skeletal muscle. HighlightsWe analysed thigh muscle quality and inflammatory signalling in young and old men.Older muscle had a greater content of non‐contractile intramuscular tissue (NCIT).The skeletal muscle of endurance trained vs. untrained men contained less NCIT.Muscle perimysium tended to be more ramified in older individuals.Differences were observed in signalling for protein turnover but not inflammation.

Novel speed test for evaluation of badminton-specific movements.

Abstract Madsen, CM, Karlsen, A, and Nybo, L. Novel speed test for evaluation of badminton-specific movements. J Strength Cond Res 29(5): 1203–1210, 2015—In this study, we developed a novel badminton-specific speed test (BST). The test was designed to mimic match play. The test starts in the center of the court and consists of 5 maximal actions to sensors located in each of the 4 corners of the court. The 20 actions are performed in randomized order as dictated by computer screen shots displayed 1 second after completion of the previous action. We assessed day-to-day variation in elite players, and specificity of the test was evaluated by comparing 30-m sprint performance and time to complete the BST in 20 elite players, 21 skilled players, and 20 age-matched physical active subjects (non-badminton players). Sprint performance was similar across groups, whereas the elite players were significantly (p ⩽ 0.05) faster in the BST (total test time: 32.3 ± 1.1 seconds; average: 1.6 seconds per action) than the skilled (34.1 ± 2.0 seconds) and non-badminton players (35.7 ± 1.7 seconds). Day-to-day coefficient of variation (CV) of the BST was 0.7% for the elite players, whereas CV for repeated tests on the same day was 1.7% for elite, 2.6% for skilled, and 2.5% for non-badminton players. On this basis, we suggest that the BST may be valuable for evaluation of short-term maximal movement speed in badminton players. Thus, the BST seems to be sport specific, as it may discriminate between groups (elite, less trained players, and non-badminton players) with similar sprinting performance, and the low test-retest variation may allow for using the BST to evaluate longitudinal changes, for example, training effects or seasonal variations.

Inflammation Relates to Resistance Training–induced Hypertrophy in Elderly Patients

Purpose Aging is associated with a gradual loss of muscle mass, which some have suggested to be accelerated by short periods of muscle disuse due to medical illness. We investigated the effect of hospitalization on skeletal muscle mass in acutely ill geriatric patients with focus on the relationship between systemic inflammatory marker C-reactive protein (CRP) and changes in muscle mass, as well as the influence of resistance training upon muscle mass. Method Unilateral leg press resistance exercise was conducted daily during the hospital period. Outcomes included changes in whole body and regional lean mass, maximal voluntary contraction of the knee extensors, leg extension power, and functional performance. Activity level was measured using ActivPAL accelerometers, and CRP levels were obtained from blood samples. Results Sixteen subjects completed the study (eight men and eight women, age = 84.8 ± 1.9 yr, mean ± SE). Lean mass at the midthigh region of the trained leg increased by 2.4% ± 1.1% (P < 0.05) after the intervention period. There was a negative association between changes in midthigh lean mass of the trained leg and CRP (rs = −0.53, P < 0.05). Leg extension power increased significantly in both legs (P < 0.05), with no difference observed between legs. There were no changes in maximal voluntary contraction or functional performance. Conclusion Muscle mass is not significantly lost during short-term hospitalization of relatively high functioning and active geriatric patients although our findings are potentially affected by changes in hydration status. Resistance training during hospitalization increases skeletal muscle mass, and patients with high levels of systemic inflammation demonstrate less ability to increase or preserve muscle mass in response to resistance training during illness.

Age-related decline in mitral peak diastolic velocities is unaffected in well-trained runners

Abstract Objectives. We examined whether diastolic left ventricular function in young and senior lifelong endurance runners was significantly different from that in sedentary age-matched controls, and whether lifelong endurance running appears to modify the age-related decline in diastolic left ventricular function. Design. The study comprised 17 senior athletes (age: 59–75 years, running distance: 30–70 km/week), 10 young athletes (age: 20–36 years, matched for running distance), and 11 senior and 12 young weight-matched sedentary controls. Peak early (E) and late (A) mitral inflow and early (e’) and late (a’) diastolic and systolic (s’) annular longitudinal tissue Doppler velocities were measured by echocardiography during four stages (rest, supine bike exercise at 30% and 60% of maximal workload, and recovery). Results. The athletes had marked cardiac remodeling, while overall differences in mitral inflow and annular tissue Doppler velocities during rest and exercise were more associated with age than with training status. The senior participants had lower E/A at rest, overall lower E, e’ and s’, and greater E/e’ compared to the young participants (all values of P < 0.05). The athletes had greater E/A (P = 0.004), but tissue Doppler velocities were not different from those of the controls. Conclusions. Lifelong endurance running was not found to be associated with major attenuation of the age-related decline in diastolic function at rest or during exercise.

Skin autofluorescence is associated with arterial stiffness and insulin level in endurance runners and healthy controls - Effects of aging and endurance exercise

Background: Life‐long regular endurance exercise yields positive effects on cardiovascular and metabolic function, disease and mortality rate. Glycation may be a major mechanism behind age‐related diseases. However, it remains unknown if skin autofluorescence (SAF), which reflects glycation, is related to arterial and metabolic function in life‐long endurance runners and sedentary controls. Methods: Healthy elderly men: 15 life‐long endurance runners (OT) (64 ± 4 years) and 12 old untrained (OU) (66 ± 4 years), and healthy young men; ten young athletes (YT) (26 ± 4 years) matched to OT for running distance, and 12 young untrained (YU) (24 ± 3 years) were recruited. Endothelial function (reactive hyperemia index, RHI) and arterial stiffness (augmentation index, AI@75 and AI) were measured by an operator‐independent PAT 2000. SAF was non‐invasively determined using an autofluorescence spectrometer. Results: For AI@75 there was an effect of age (p < 0.0001), but not training (p = 0.71). There was an interaction for endothelial function (p < 0.05): YT had higher RHI than YU (p < 0.05) and OU (p < 0.01). SAF was associated with arterial stiffness (r2 = 0.57, p < 0.001), insulin and HOMA‐index levels after age correction (both r2 = 0.19, p < 0.05). Conclusions: To our knowledge, these are the first data to show that skin autofluorescence (SAF) is linked to human arterial stiffness and insulin resistance in well‐trained elderly and young men as well as sedentary controls. SAF may in the future be a helpful tool to predict vascular and metabolic dysfunction (early signs of aging and pathology). Surprisingly, endurance running only had modest effects on cardiovascular function compared to lean healthy controls.