Aerobically trained older adults show impaired resting, but preserved exercise-induced circulating progenitor cell count, which was not improved by sprint interval training.

Older adults exhibit a reduced number and function of CD34 + circulating progenitor cells (CPC), a known risk factor for cardiovascular disease. Exercise promotes the mobilisation of CPCs from bone marrow, so whether ageing per se or physical inactivity in older age reduces CPCs is unknown. Thus, this study examined the effect of age on resting and exercise-induced changes in CPCs in aerobically trained adults and the effect of 8 weeks of sprint interval training (SIT) on resting and exercise-induced CPCs in older adults. Twelve young (22-34 years) and nine older (63-70 years) adults participated in the study. Blood was sampled pre and immediately post a graded exercise test to exhaustion in both groups. Older participants repeated the process after 8 weeks of SIT (3 × 20 s 'all-out' sprints, 2 × a week). Total CPCs (CD34+) and endothelial progenitor cells (EPCs: CD34+KDR+) were determined by flow cytometry. Older adults exhibited lower basal total CD34+ CPCs (828 ± 314 vs. 1186 ± 272 cells·mL-1, p = 0.0149) and CD34+KDR+ EPCs (177 ± 128 vs. 335 ± 92 cells·mL-1, p = 0.007) than younger adults. The maximal exercise test increased CPCs in young (CD34+: p = 0.004; CD34+KDR+: p = 0.017) and older adults (CD34+: p < 0.001; CD34+KDR+: p = 0.008), without difference between groups (p = 0.211). SIT did not alter resting or exercise-induced changes in CPCs in the older cohort (p > 0.232). This study suggests age per se does not impair exercise-induced CPC counts, but does lower resting CPC counts.

High Intensity Interval Training (HIIT) as a Potential Countermeasure for Phenotypic Characteristics of Sarcopenia: A Scoping Review.

Background: Sarcopenia is defined as a progressive and generalized loss of skeletal muscle quantity and function associated predominantly with aging. Physical activity appears the most promising intervention to attenuate sarcopenia, yet physical activity guidelines are rarely met. In recent years high intensity interval training (HIIT) has garnered interested in athletic populations, clinical populations, and general population alike. There is emerging evidence of the efficacy of HIIT in the young old (i.e. seventh decade of life), yet data concerning the oldest old (i.e., ninth decade of life onwards), and those diagnosed with sarcopenic are sparse. Objectives: In this scoping review of the literature, we aggregated information regarding HIIT as a potential intervention to attenuate phenotypic characteristics of sarcopenia. Eligibility Criteria: Original investigations concerning the impact of HIIT on muscle function, muscle quantity or quality, and physical performance in older individuals (mean age ≥60 years of age) were considered. Sources of Evidence: Five electronic databases (Medline, EMBASE, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials [CENTRAL]) were searched. Methods: A scoping review was conducted using the Arksey and O'Malley methodological framework (2005). Review selection and characterization were performed by two independent reviewers using pretested forms. Results: Authors reviewed 1,063 titles and abstracts for inclusion with 74 selected for full text review. Thirty-two studies were analyzed. Twenty-seven studies had a mean participant age in the 60s, two in the 70s, and three in the 80s. There were 20 studies which examined the effect of HIIT on muscle function, 22 which examined muscle quantity, and 12 which examined physical performance. HIIT was generally effective in Improving muscle function and physical performance compared to non-exercised controls, moderate intensity continuous training, or pre-HIIT (study design-dependent), with more ambiguity concerning muscle quantity. Conclusions: Most studies presented herein utilized outcome measures defined by the European Working Group on Sarcopenia in Older People (EWGSOP). However, there are too few studies investigating any form of HIIT in the oldest old (i.e., ≥80 years of age), or those already sarcopenic. Therefore, more intervention studies are needed in this population.

Sprint interval training (SIT) reduces serum epidermal growth factor (EGF), but not other inflammatory cytokines in trained older men.

PURPOSE: The present study aimed to investigate the effect of age on circulating pro- and anti-inflammatory cytokines and growth factors. A secondary aim was to investigate whether a novel sprint interval training (SIT) intervention (3 × 20 s 'all out' static sprints, twice a week for 8 weeks) would affect inflammatory markers in older men. METHODS: Nine older men [68 (1) years] and eleven younger men [28 (2) years] comprised the younger group. Aerobic fitness and inflammatory markers were taken at baseline for both groups and following the SIT intervention for the older group. RESULTS: Interleukin (IL)-8, vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1) were unchanged for the older and younger groups at baseline (IL-8, p = 0.819; MCP-1, p = 0.248; VEGF, p = 0.264). Epidermal growth factor (EGF) was greater in the older group compared to the younger group at baseline [142 (20) pg mL-1 and 60 (12) pg mL-1, respectively, p = 0.001, Cohen's d = 1.64]. Following SIT, older men decreased EGF to 100 (12) pg mL-1 which was similar to that of young men who did not undergo training (p = 0.113, Cohen's d = 1.07). CONCLUSION: Older aerobically trained men have greater serum EGF than younger aerobically trained men. A novel SIT intervention in older men can shift circulating EGF towards trained younger concentrations. As lower EGF has previously been associated with longevity in C. elegans, the manipulative effect of SIT on EGF in healthy ageing in the human may be of further interest.

Peak Power Output Is Similarly Recovered After Three- and Five-Days' Rest Following Sprint Interval Training in Young and Older Adults.

(1) Background: High-intensity interval training (HIIT) exerts effects indicative of improved health in young and older populations. However, prescribing analogous training programmes is inappropriate, as recovery from HIIT is different between young and older individuals. Sprint interval training (SIT) is a derivative of HIIT but with shorter, maximal effort intervals. Prior to prescribing this mode of training, it is imperative to understand the recovery period to prevent residual fatigue affecting subsequent adaptations. (2) Methods: Nine older (6M/3F; mean age of 70 ± 8 years) and nine young (6M/3F; mean age of 24 ± 3 years) participants performed a baseline peak power output (PPO) test. Subsequently, two SIT sessions consisting of three repetitions of 20 s 'all-out' stationary cycling bouts interspersed by 3 minutes of self-paced recovery were performed. SIT sessions were followed by 3 days' rest and 5 days' rest on two separate occasions, in a randomised crossover design. PPO was measured again to determine whether recovery had been achieved after 3 days or after 5 days. (3) Results: Two-way repeated measure (age (older, young) × 3 time (baseline, 3 days, 5 days)) ANOVA revealed a large effect of age (p = 0.002, n2p = 0.460), with older participants having a lower PPO compared to young participants. A small effect of time (p = 0.702, n2p = 0.022), and a medium interaction between age and time (p = 0.098, n2p = 0.135) was observed. (4) Conclusions: This study demonstrates both young and older adults recover PPO following 3 and 5 days' rest. As such, both groups could undertake SIT following three days of rest, without a reduction in PPO.