Elite athletes have longer telomeres than sedentary subjects: A meta-analysis

Effect of Exercise on Acute Senescent Lymphocyte Counts: A Systematic Review and Meta-Analysis

BACKGROUND

Highly differentiated, senescent lymphocytes are pro-inflammatory and contribute to age-related systemic inflammation, called inflammageing. There are several reports of acute changes in senescent lymphocyte counts post exercise, which potentially have consequences for systemic inflammation. However, there is little consensus since the studies differ with respect to participants, exercise protocols, cellular markers assessed, and the time point of assessment post exercise.

OBJECTIVE

We performed a systematic review and meta-analysis to assess the impact of exercise on senescent lymphocyte counts in blood immediately, 1 h and 2 h post exercise.

METHODS

The search was performed in PubMed (MEDLINE), Web of Science, Embase, Scopus, and Cochrane, on January 11, 2021. The 13 studies selected tested aerobic exercise effects, mainly in young men. They assessed the counts of lymphocytes (CD4 T cells, CD8 T cells, and NK cells), with the following immune cell marker combinations: KLRG1+, CD57+ (only NK cells), EMRA T cells (CD45RA+CCR7-CD28-CD27-), CD28-CD27-, KLRG1+CD28-, and CD28-. Independent extraction of articles was done by 2 researchers.

RESULTS

Standardized mean difference (SMD) and 95% confidence interval between baseline and post exercise showed significant increase (SMD >0.9, p < 0.003) in all types of senescent lymphocytes counts immediately post exercise. At 1 h post exercise, senescent CD4 T cells returned to baseline values (p = 0.74), CD8 T cells were reduced (-0.26 [-0.41; -0.11], p = 0.001), and senescent NK cells were raised (0.62 [0.14; 1.10], p = 0.01) above baseline. By 2 h post exercise, senescent CD4 T cells were reduced (-0.94 [-1.40; -0.48], p < 0.001), CD8 T cells remained below baseline (-0.53 [-1.04; -0.009], p = 0.04), and NK cells had returned to baseline values (-0.29 [-0.64; 0.07], p = 0.11). The main determinants of heterogeneity between studies were cytomegalovirus (CMV) serostatus and the characteristics of exercise protocols. CMV+ individuals had a higher immediate lymphocytosis and 1 h post lymphopenia than CMV- individuals. Exercise performed at higher intensities and shorter durations led to higher magnitude of change in senescent lymphocyte counts at all time-points.

CONCLUSION

The differing effects of exercise on senescent NK cells and CD4 and CD8 T cells suggest differing susceptibility to factors modulating lymphocyte extravasation such as adrenaline and exercise intensity.

Exercise training increases telomerase reverse transcriptase gene expression and telomerase activity: A systematic review and meta-analysis

Telomeres protect genomic stability and shortening is one of the hallmarks of ageing. Telomerase reverse transcriptase (TERT) is the major protein component of telomerase, which elongates telomeres. Given that short telomeres are linked to a host of chronic diseases and the therapeutic potential of telomerase-based therapies as treatments and a strategy to extend lifespan, lifestyle factors that increase TERT gene expression and telomerase activity could attenuate telomere attrition and contribute to healthy biological ageing. Physical activity and maximal aerobic fitness are associated with telomere maintenance, yet the molecular mechanisms remain unclear. Therefore, the purpose of this systematic review and meta-analysis was to identify the influence of a single bout of exercise and long-term exercise training on TERT expression and telomerase activity. A search of human and rodent trials using the PubMed, Scopus, Science Direct and Embase databases was performed. Based on findings from the identified and eligible trials, both a single bout of exercise (n; standardised mean difference [95%CI]: 5; SMD: 1.19 [0.41-1.97], p = 0.003) and long-term exercise training (10; 0.31 [0.03-0.60], p = 0.03) up-regulates TERT and telomerase activity in non-cancerous somatic cells. As human and rodent studies were included in the meta-analyses both exhibited heterogeneity (I² = 55-87%, p < 0.05). Endurance athletes also exhibited increased leukocyte TERT and telomerase activity compared to their inactive counterparts. These findings suggest exercise training as an inexpensive lifestyle factor that increases TERT expression and telomerase activity. Regular exercise training could attenuate telomere attrition through a telomerase-dependent mechanism and ultimately extend health-span and longevity.

Age and Sport Intensity-Dependent Changes in Cytokines and Telomere Length in Elite Athletes

Exercise-associated immune response plays a crucial role in the aging process. The aim of this study is to investigate the effect of sport intensity on cytokine levels, oxidative stress markers and telomere length in aging elite athletes. In this study, 80 blood samples from consenting elite athletes were collected for anti-doping analysis at an anti-doping laboratory in Italy (FMSI). Participants were divided into three groups according to their sport intensity: low-intensity skills and power sports (LI, n = 18); moderate-intensity mixed soccer players (MI, n = 31); and high-intensity endurance sports (HI, n = 31). Participants were also divided into two age groups: less than 25 (n = 45) and above 25 years old (n = 35). Serum levels of 10 pro and anti-inflammatory cytokines and two antioxidant enzymes were compared in age and sport intensity groups and telomere lengths were measured in their respective blood samples. Tumor necrosis factor-alpha (TNF-α) was the only cytokine showing significantly higher concentration in older athletes, regardless of sport intensity. Interleukin (IL)-10 increased significantly in HI regardless of age group, whereas IL-6 concentration was higher in the older HI athletes. IL-8 showed a significant interaction with sport intensity in different age groups. Overall, significant positive correlations among levels of IL-6, IL-10, IL-8 and TNF-α were identified. The antioxidant catalase activity was positively correlated with levels of TNF-α. Telomere length increased significantly with sport intensity, especially in the younger group. HI had longer telomeres and higher levels of pro- and anti-inflammatory cytokines, suggesting less aging in HI compared to low and moderate counterparts in association with heightened immune response. Investigation of the functional significance of these associations on the health and performance of elite athletes is warranted.

Effect of physical activity and exercise on telomere length: Systematic review with meta-analysis

PURPOSE

To compare a physically active lifestyle or structured exercise program to physically inactive lifestyle or control groups on telomere length (TL).

METHOD

We searched PubMed, EMBASE, Cochrane Library, and Open Gray databases up to March 31, 2020. We calculated standardized mean differences (SMD) with 95% confidence intervals (CI) of TL comparing physically active to physically inactive individuals and exercise intervention to control groups. Risk of bias was judged using the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for physical activity (PA) studies and the Cochrane risk-of-bias (RoB2) for exercise intervention studies. Certainty of evidence was judged using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

We included 30 studies (24 assessing the effects of PA and 6 assessing the effects of exercise interventions) comprising 7418 individuals. Physically active individuals had longer telomeres (SMD = 0.70, 95% CI 0.12-1.28, very-low certainty), especially in middle-aged individuals (SMD = 0.90, 95% CI 0.08-1.72, very-low certainty) and when considering only athletes (SMD = 0.54, 95% CI 0.18-0.90, very-low certainty). Trim-and-fill analyses revealed that most of the pooled effects were overestimated. Exercise interventions did not yield any significant effect on TL.

CONCLUSION

There is very-low certainty that physically active individuals have longer telomeres with a moderate effect, but this effect is probably overestimated.

Master athletes have longer telomeres than age-matched non-athletes. A systematic review, meta-analysis and discussion of possible mechanisms

The aim of this systematic review and meta-analysis was 1) to assess whether master athletes have longer telomeres than age-matched non-athletes and 2) discuss possible underlying mechanisms underlying telomere length preservation in master athletes. A literature search was performed in PubMed, Web of Science, Scopus and SPORTDiscus up to August 2020. Only original articles published in peer-reviewed journals that compared telomere length between master athletes and aged-matched non-athletes were included. Eleven studies fulfilled eligibility criteria and were included in the final analysis. Overall, 240 master athletes (51.9±7.5 years) and 209 age-matched non-athletes (50.1±9.1 years) were analyzed. Master athletes had been participating in high-level competitions for approximately 16.6 years. Pooled analyses revealed that master athletes had longer telomeres than aged-matched non-athletes (SMD=0.89; 95% CI=0.45 to 1.33; p<0.001). Master athletes showed lower pro-oxidant damage (SMD=0.59; 95% CI=0.26 to 0.91; p<0.001) and higher antioxidant capacity (SMD=-0.46; 95% CI=-0.89 to -0.03; p=0.04) than age-matched non-athletes. Further, greater telomere length in master athletes is associated with lower oxidative stress and chronic inflammation, and enhanced shelterin protein expression and telomerase activity. In conclusion, 1) master athletes have longer telomeres than age-matched non-athletes, which may be the result of 2) lower levels of oxidative stress and chronic inflammation, and elevated shelterin expression and telomerase activity.

Stress, Professional Lifestyle, and Telomere Biology in Elite Athletes: A Growing Trend in Psychophysiology of Sport

Professional lifestyle and championship period often put a great deal of pressure on athletes, who usually experience highly stressful periods during training for competitions. Recently, biomarkers of cellular aging, telomere length (TL) and telomerase activity (TA), have been considered to investigate the effects of stress and lifestyle factors. Studies in non-athletic populations have shown that stress and poor lifestyle decrease TL and TA. On the other hand, it has been shown that in general, exercise increases TL and its activity, although the underlying mechanisms remained largely unexplored. TL and TA outcomes in elite athletes remain inconclusive and mainly affected by confounding factors, such as age. Elite athletes, therefore, might offer a unique target group for studying exercise-telomere hypothesis for further investigation of the roles of stressors on telomere-related biomarkers. In this perspective, we highlight the potentials for studying these psychophysiological markers in elite athletes in order to understand stress-aging relationship and potential underlying mechanisms. Moreover, we present important methodological aspects that could help in the development of future experimental designs.