Background: It is well known that ultra-endurance races such as a full distance ironman triathlon causes damage to skeletal and cardiac muscles. However, the underlying factors causing these disturbances are less investigated. In this study we investigated if there is an association between ground reaction forces, measured with accelerometry, during the marathon part of an Ironman triathlon and markers of skeletal and cardiac muscle damage. Our hypothesis is that higher ground reaction forces is positively associated with skeletal and heart muscle damage with no difference between the genders in this association.

Methods: In all 20 (8 women) subjects completed a full distance ironman triathlon (3.8 km swimming, 180 km cycling and 42 km running) and provided a full set of data and was included in the analysis. As markers for skeletal muscle damage, creatin kinas (CK) and myoglobin was analysed. As markers for cardiac muscle damage cardiac troponin t (cTnT), the N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) was analysed. Ground reaction forces was estimated using an accelerometer (ActiGraph GT3x). Based on the official transition times we sliced out the raw accelerations for the marathon part of the race and calculated the mean vector magnitude (VM) expressed in milliG per second (mG/s). Due to outliers among the dependent variables, Spearman rank correlations (rho) stratified by sex was calculated.

Results: As seen in figure 1, no significant association between the biomarkers and mechanical stress was observed (all p>0.05).

Conclusion: We did not find any support to our initial hypothesis that there should be a positive association between ground reaction forces and markers of skeletal and heart muscle damage. The small sample size in the groups and the fact that we did not adjust for any potential confounder in this study warrants causing in the interpretation of the results. 

Purpose: The aim of this study was to investigate the chemokines profile in patients treated for neovascular age-related macular degeneration (nAMD) treated with anti-VEGF injections.

Methods: The study was conducted in a hospital in Sweden. Patients diagnosed with nAMD (ICD 10 Diagnosis Code H353) and who were scheduled for treatment with an intravitreal anti-VEGF injection were invited to take part. Patients must have had at least 3 injections prior to the invitation to the study (treat-and-extend or pro-re-nata regimen). Venous blood samples were collected before the injection according to clinical guidelines for phlebotomy using EDTA tubes. Samples were centrifuged at 3000 x g at 4°C for 15 minutes to isolate plasma. The chemokines in the plasma were analysed using a Bio-Plex Human Cytokine kit. Median concentrations for each chemokine were compared between the two groups.

Results: The study included data from one hundred and fifty patients with nAMD, a mean age of 79 years (range 56-98) and 101 (67%) were female. The median acuity in the better eye was 0.22 logMAR (IQR=0.36). The study also included data from 46 controls, mean age 75 years (range 85-71) and 26 (57%) were females. The analysis revealed significant differences in chemokines expression in the nAMD group compared to the control group. Amongst others, it revealed elevated expression of MCP-1 or CCL2 (p<0.001) and MIP-1alpha or CCL3 (p<0.001) and reduced expression for MIP-1beta or CCL4 (p<0.001).

Conclusions: Results of the current study reveal that patients with nAMD have differences in chemokine expression compared to controls. The chemokines which were altered in the patient group may be involved in disease relapse and interfere with the course of the disease during the treatment period.

BackgroundA growing body of evidence suggests that exposure to nature is beneficial for human health. However, the observed health effect of nature may be mediated by physical activity and that humans are physically active at a higher intensity outdoors compared to when they are physical active indoors.ObjectiveThis study examines the variation of heart rate and power output for a fixed rating of perceived exertion in a group of healthy older adults in three different environments representing three levels of exposure to nature.MethodsTo this randomized, 3-by-3 crossover design study, healthy older adults (≥65 years) were recruited from local gyms. All participants participated in three experimental conditions; indoors, simulated outdoors and outdoor environments, in a randomized order. The participants exercised for 20 minutes at an intensity equivalent to a rating of 11–13 on the Borg scale for perceived exertion (RPE). Measurements of heart rate, power output (Watt) and ratings of perceived exertion were taken at minutes 1 to 6 and at minute 20. To examine the effect of the environment on heart rate and power, linear mixed models were used.ResultsIn all, 48 participants (56% females) were included in the analysis. No significant main effects on the outcomes were observed for power output (p = 0.073, η2 = 0.04) or heart rate (p = 0.067, η2 = 0.04)ConclusionNo significant effect on the outcomes was observed. However, borderline significant outcomes for power output or heart rate outdoors in nature, along with previous studies in the field, indicates that such an effect cannot be completely ruled out, but any effect is likely to be small. Future research examining health benefits of the independent exposure to nature are encouraged to adjust for the dose of physical activity.

This study examines the association between aerobic capacity and biomarkers of skeletal- and cardiac muscle damage among amateur triathletes after a full distance Ironman. Men and women (N = 55) were recruited from local sport clubs. One month before an Ironman triathlon, they conducted a 20 m shuttle run test to determine aerobic capacity. Blood samples were taken immediately after finishing the triathlon, and analyzed for cardiac Troponin T (cTnT), Myosin heavy chain-a (MHC-a), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), Creatin Kinas (CK), and Myoglobin. Regression models examining the association between the biomarkers and aerobic capacity expressed in both relative terms (mLO2*kg−1*min−1) and absolute terms (LO2*min−1) controlled for weight were fitted. A total of 39 subjects (26% females) had complete data and were included in the analysis. No association between aerobic capacity and cardiac muscle damage was observed. For myoglobin, adding aerobic capacity (mLO2*kg−1*min−1) increased the adjusted r2 from 0.026 to 0.210 (F: 8.927, p = 0.005) and for CK the adjusted r2 increased from -0.015 to 0.267 (F: 13.778, p = 0.001). In the models where aerobic capacity was entered in absolute terms the adjusted r2 increased from 0.07 to 0.227 (F: 10.386, p = 0.003) for myoglobin and for CK from -0.029 to 0.281 (F: 15.215, p < 0.001). A negative association between aerobic capacity and skeletal muscle damage was seen but despite the well-known cardio-protective health effect of high aerobic fitness, no such association could be observed in this study.

In this study we have investigated the effectiveness of a one day school-basedintervention with recreational fishing (in Swedish called Klassdraget) in increasingenvironmental awareness, interest in nature and recreational fishing in pupils agedbetween 8 and 12. Our results suggest a weak positive association between exposure tonatural environments in a recreational fishing context and interest in nature andrecreational fishing. We found the intervention to have no effect on the frequency offishing, interest in fishing more, or number of visits in nature during spare time.Knowledge about nature and possibly also environmental awareness are positivelyaffected and these effects can be traced as long as three years after the intervention. Ourfindings also reveal a low correlation between frequency of nature visits and selfreportedinterest in nature. The observed effects of Klassdraget are small but appear tobe larger for girls, who are traditionally less interested in recreational fishing whencompared with boys.

Purpose: The purpose of this study was to test the hypothesis that the ”outdoors” has an added health effect on top of that of physical activity. This hypothesis is based on the fairly extensive volume of evidens suggesting that the outdoor environment is beneficial for overall health. We, however, consider most previous studies insufficiently designed in order to draw causal relationship between spending time outdoors and examined health parameters. In this study we state that our experimental design allows us to do just that. 

Methods:

In this randomized cross-over experimental design, 49 healthy subjects (+65 years, 27 female) performed a standardized submaximal bike ergometer test in three different environments (indoors, simulated outdoors and outdoors). The test consisted of 20 minutes cycling and subjects were instructed to stay between 11-13 at the Borg RPE scale (i.e. moderate intensity). Each test was followed by two hours of passive recovery. We measured power output, heart rate, lactate and counts of five fractions (lymphocytes, monocytes, neutrophiles, basophiles and eosinophiles) of white blood cells (leukocytes) in circulation.

Results:

Our results revealed that the outdoor treatment resulted in higher levels of lactate, higher heart rate and higher power output despite that there were no differences in Borg RPE-rating between the treatments. The white blood cell analysis showed an increase of circulating leukocytes in almost all fractions immediately post exercise in all treatments. Numbers decreased rapidly post exercise and the lymphocyte numbers stayed well under baseline for more than one hour during recovery. This is referred to as an “open window” where the immune function is temporarily suppressed and there is an elevated risk of infection of primarily URTI.

Conclusions:

Our results not only suggest that exercise is more efficient out of doors such that more exercise/effort is obtained but also that recovery outdoors may be a way to decrease the risk of infections due to exercise induced immune suppression. The risk of getting an infection is known to be generally lower out of doors. Taken together, our results support the notion that exercising and spending time outdoors indeed is beneficial for health in senior citizens.

INTRODUCTION: IntroductionPhysical exercise has been proven beneficial for health in all ages. In elderly, physical exercise, may contribute to prolonged life with maintained high quality and less costs associated with health care for society. In this study we explore if exercise out of doors may provide extra benefits as compared to exercise indoors and we measure power output, lactate levels and perceived effort in 49 senior citizens performing 20 minutes of moderate physical activity.METHODS:MethodThe HERO project is a randomized cross-over experiment with three different treatments <indoors, simulated="" outdoors="" and="">. The study sample consisted of 49 healthy senior citizens. They performed 20 minutes moderate intensity physical activity on an ergometer bike in all three conditions. Before immediately after and at minutes 10, 20, 30, 60 and 120 we sampled blood lactate. Power output was computed at 7 occasions during the 20 minutes of cycling, as was the rating of perceived exertion . Data was analyzed using mixed linear models. RESULTS:ResultsOur findings show that there were no differences between the two indoor treatments in any of the measured variables. In the outdoor treatment, however, there were significant effects on blood lactate levels and power output but not in perceived exertion, suggesting that exercise out of doors makes the test person more efficient although the experience of effort stay unaffected.CONCLUSION:Discussion/conclusionsOur results support the notion that the outdoors may provide extraordinary conditions for exercise, not only because it appear to results in more exercise/effort, the outdoors is also an “arena” with high availability and most often totally for free. Previous results from the HERO project also suggests that white blood cell counts are affected by the outdoor treatment, something that may be related to the observed increased power output herein

INTRODUCTION: Ironman competitions and other extreme endurance events has spread worldwide attracting thousands of endurance-trained athletes, athletes who differ in anthropometric and training characteristics. The relationship between peak oxygen uptake and finishing- and segment time during a full distance IRONMAN competition (Swim 3.9km, Bike 180km and Run 42.2km) has not been examined thoroughly in non-elite athletes.

PURPOSE: The aim of the present study was to investigate the relationship between peak oxygen uptake (VO₂peak), finishing time and segment time in non-elite athletes.

METHODS: 39 non-elite athletes (10 female; age 41.1 ± 9.7, range 24-70 years) performed a 20 m shuttle run test to assess VO₂peak. Association between VO₂ and finishing- and segment time was estimated using bivariate correlation tests. Gender specific analysis was also performed.

RESULTS: VO₂peak peak was on average 49.9 ± 6.4 O2 ml/kg/minute, range 36.5-63.9 (pooled genders). Finishing time was on average 11h and 52 min. The average times for the different segments were; Swim 1h 21m, Bike 5h 46min and Run 4h 33min. The relationship between VO₂peak and finishing time was significant to p<0.001 and                         0.51. The relationship between segment times were Swim  0.19, Bike  0.37 and Run  0.46 all at p<0.001. Gender specific analyses revealed that the association between VO₂peak and finishing time was   0.80 for females and  0.49 for males. 

CONCLUSION: Our results suggest that VO₂peak is a good predictor of finishing time (approx. 50%) as well as for segment time with 19%, 37% and 46% for Swim, Bike and Run respectively (pooled genders). For females VO₂peak explains as much as 80% of the variation in finishing time.

BACKGROUND: While overall physical activity is clearly associated with a better short-term and long-term health, prolonged strenuous physical activity may result in a rise in acute levels of blood-biomarkers used in clinical practice for diagnosis of various conditions or diseases. In this study, we explored the acute effects of a full Ironman-distance triathlon on biomarkers related to heart-, liver-, kidney- and skeletal muscle damage immediately post-race and after one week's rest. We also examined if sex, age, finishing time and body composition influenced the post-race values of the biomarkers.

METHODS: A sample of 30 subjects was recruited (50% women) to the study. The subjects were evaluated for body composition and blood samples were taken at three occasions, before the race (T1), immediately after (T2) and one week after the race (T3). Linear regression models were fitted to analyse the independent contribution of sex and finishing time controlled for weight, body fat percentage and age, on the biomarkers at the termination of the race (T2). Linear mixed models were fitted to examine if the biomarkers differed between the sexes over time (T1-T3).

RESULTS: Being male was a significant predictor of higher post-race (T2) levels of myoglobin, CK, and creatinine levels and body weight was negatively associated with myoglobin. In general, the models were unable to explain the variation of the dependent variables. In the linear mixed models, an interaction between time (T1-T3) and sex was seen for myoglobin and creatinine, in which women had a less pronounced response to the race.

CONCLUSION: Overall women appear to tolerate the effects of prolonged strenuous physical activity better than men as illustrated by their lower values of the biomarkers both post-race as well as during recovery.

Introduction

Natural environments are known to promote health and may also provide extraordinary conditions for post exercise recovery (Kuo 2015). In the project Health Effects of Recreation Outdoors (HERO) we explore the hypothesis that post exercise recovery in natural environments may be reflected in white blood cell counts (WBC). In our study 50 seniors (age >65 years) performed moderate physical activity (20 min) followed by passive recovery (2h) in three different environments (indoors, simulated outdoors and “true” outdoors).

Method

The experimental setup was a randomized cross-over design, thus all test persons did all treatments in a randomized order. We sampled white blood cells (WBC-diff), which were used to detect and quantify inflammatory response.

Results

Our early findings provide some support for the hypothesis that environment may impose differences in recovery effectiveness. White blood cell count (WBC-diff) appears to differ between the treatments and there is a significant interaction between sampling time and recovery environment in the monocytes, suggesting that the monocyte numbers differ, not only between sampling times but also between environments. In addition, WBC also show that some of the test persons develop leukocytosis during exercise and that white blood cell levels decrease rapidly immediately post exercise to levels significantly lower than base line values.

Discussion

Our results suggest that moderate physical activity in senior citizens may result in acute leukocytosis (see e.g. Sand et. al. 2013) and that recovery effectiveness (e.g in monocyte response) may be dependent upon environmental factors. The clinical importance of our results are not fully understood but there has been suggested an “open window” immediately post exercise in which infection risk may be elevated (Pedersen & Toft 2000) and it is possible that recovery out of doors may reduce this risk.

References

Sand, K., L, Flatebo, K., Andersen, M., B., Maghazachi, A., A. (2013) World J Exp Med 20; 3(1): 11-20

Pedersen, B., K. & Toft, A., D. (2000) Br J Sports Med 34:246–251

Kuo, M. (2015) Frontiers in Psychology 6:1-8