Aging and Thermoregulatory Control: The Clinical Implications of Exercising under Heat Stress in Older Individuals

Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016

As climate change causes global temperatures to rise, heat-related illness, a potentially fatal condition in dogs, will become an ever-greater threat. This study aimed to report the incidence, fatality and canine risk factors of heat-related illness in UK dogs under primary veterinary care in 2016. The VetCompass^TM programme collects de-identified electronic patient records from UK veterinary practices for research. From the clinical records of 905,543 dogs under veterinary care in 2016, 395 confirmed heat-related illness events were identified. The estimated 2016 incidence of heat-related illness was 0.04% (95% CI 0.04-0.05%), with an event fatality rate of 14.18% (95% CI 11.08 – 17.96%). Multivariable analysis identified significant risk factors including breed (e.g. Chow Chow, Bulldog and French Bulldog), higher bodyweight relative to the breed/sex mean and being over two years of age. Dogs with a brachycephalic skull shape and dogs weighing over 50 kg were also at greater risk. As we move into an ever-warmer world, veterinary professionals may need to include resistance to heat-related illness amongst their rationales when advising owners on breed selection. Breeding for good respiratory function and maintaining a healthy bodyweight should be considered key welfare priorities for all dogs to limit the risk of heat-related illness.

Real-Time Monitoring of the Effects of Personal Temperature Exposure on the Blood Oxygen Saturation Level in Elderly People with and without Chronic Obstructive Pulmonary Disease: A Panel Study in Hong Kong

Few studies have investigated the short-term effect of personal temperature exposure on blood oxygen saturation (SpO₂). We conducted this longitudinal panel study with real-time monitoring of SpO₂ and environmental exposure for 3 continuous days for 20 patients with chronic obstructive pulmonary disease (COPD) and 20 healthy volunteers in Hong Kong, to explore the time course (from minutes to hours) of change in SpO₂ in response to temperature in elderly people. We employed a generalized additive mixed model to evaluate the acute effects of personal temperature exposure on changes in SpO₂ and risk of oxygen desaturation while adjusting for seasonality, environmental co-exposures, and personal characteristics. We observed a concurrent decline in SpO₂ by 0.27% (95% confidence interval [CI]: 0.22-0.32%) and an increase in the risk of oxygen desaturation by an OR of 1.14 (95% CI, 1.10-1.18) associated with a 1 °C increase in personal temperature, and the association lasted over several hours. Results showed that the decline in SpO₂ in elderly people was associated with an increase in personal temperature exposure within minutes to hours, particularly in women and male patients with COPD. Temperature-induced oxygen desaturation may play a pivotal role in COPD exacerbation.

Skin Temperature in Master Long-Distance Runners-Results From a Field Study at the 2018 World Master Athletics Championships

Older people and athletes show impairments in thermoregulation, but this has not yet been studied during a running competition. The aim of the study was to assess (1) whether there are age-related differences in skin temperature during the last stage of a race in well-trained master athletes and (2) to what extent such differences are related to running speed and sex. To investigate this, we used thermography to measure maximum skin temperatures of the head, legs and hands of participants of the 2018 World Master Athletics (WMA) Championships when they were approximately 9,600 m into a 10,000-m road race. Of the 813 runners, 404 were analyzed (142 women, 262 men) including athletes of age groups 35 to 85. All ≥70-year-old athletes completed the race; all 16 non-finishers were younger. The hand temperature was lower than that of the head and legs (p < 0.001). Stepwise regression revealed that head ( R adj 2 = 0.143; p < 0.001) and hand temperature decreased with increasing speed ( R adj 2 = 0.092; p < 0.001). Sex was the most important determinant of leg skin temperature ( R adj 2 = 0.054; p < 0.001), men having higher leg temperatures than women, with a small negative contribution of speed ( R adj 2 increased to 0.069). In conclusion, higher running speed is associated with lower skin temperatures, and leg skin temperature is lower in women than men. The absence of an age effect on skin temperature suggests that there is no impairment in heat dissipation in well-trained older athletes.

High Intensity Resistance Exercise Training to Improve Body Composition and Strength in Older Men With Osteosarcopenia. Results of the Randomized Controlled Franconian Osteopenia and Sarcopenia Trial (FrOST)

Considerably decreased muscle mass and function are subsumed under "sarcopenia," a geriatric syndrome. Dedicated exercise programs maintain muscle mass and function; however, due to the limited enthusiasm of older adults to exercise, it is important to generate low-threshold interventions for this vulnerable cohort. Thus, the primary aim of this study was to determine the effect of low volume/high intensity resistance exercise training (HIT-RT) combined with protein supplementation on body composition and strength in older men with sarcopenia and osteopenia (osteosarcopenia). Forty-three community-dwelling (cdw) older men (78 ± 4 years) with osteosarcopenia were randomly allocated to a consistently supervised HIT-RT (n = 21) or an inactive control group (CG, n = 22). HIT-RT scheduled a single set protocol with high intensity and effort applied twice a week for 36 weeks so far. Both groups were supplemented with Vit-D (800 IE/d), calcium (1,000 mg/d) and whey-protein (CG: 1.2 vs. HIT-RT: 1.5-1.7 g/kg/d). Study endpoints were body composition (dual-energy x-ray absorptiometry) and maximum isokinetic hip/leg-extensor strength (MIES) by leg-press. After 36 weeks, one participant who developed prostate cancer after inclusion in the study (HIT-RT) and two participants who lost interest (CG, HIT-RT) quit the study. Attendance rate for HIT-RT averaged 93 ± 5%. Total and thigh lean body mass (LBM) significantly (p < 0.001) increased in the HIT-RT and was maintained in the CG (p = 0.46 and 0.37). Differences between the groups for changes of total and thigh LBM were pronounced (p < 0.001; SMD d' = 1.17 and 1.20). Total and abdominal body fat percentage decreased significantly in the HIT-RT (p < 0.001) and increased in the CG (p = 0.039 and p = 0.097). Intergroup differences were significant (p < 0.001; SMD: d' = 1.35 and 1.28). Finally, MIES was maintained in the CG (p = 0.860), and improved significantly (p < 0.001) in the HIT-RT. Differences between the groups were significant (p < 0.001, SMD: d' = 2.41). No adverse effects of the intervention were observed. In summary, the HIT-RT/protein protocol significantly affected body composition and strength in cdw men 72 years+ with osteosarcopenia. In the absence of negative side effects, the intervention was feasible, attractive and time effective. Thus, we conclude that supervised HIT-RT might be an exercise option for older men.

Efficacy of water spray for evaporative cooling in athletes with spinal cord injury

Study design

Interventional crossover study.

Objective

Spinal cord injury (SCI) disrupts afferent input to the hypothalamus and impairs efferent vaso- and sudomotor output, especially in lesions above the sympathetic chain (T1-L2). In consequence, persons with SCI under heat stress experience impairment in the ability to dissipate heat proportional to the lesion level. Thermoregulatory dysfunction places an individual at high risk of hyperthermia, which can be life threatening, especially for athletes with SCI during exercise. Current evidence on therapeutic cooling techniques in athletes with SCI is limited, but basic physiologic and research data suggest water spray (WS) might be efficacious, particularly in athletes with tetraplegia (TP), who are most impaired in thermoregulation. The aim of this study was to evaluate the effect of WS on core temperature (Tc) during exercise in athletes with SCI.

Setting

Texas, USA.

Methods

Eleven individuals with SCI: seven with TP, four with paraplegia (PP); and sixteen able-bodied (AB) controls underwent a wheelchair intermittent sprint exercise for 90 min under two conditions: (1) WS application every 15 min and (2) control (C), without WS. Tc was measured every 15 min and was analyzed for the effect of group (TP, PP, and AB) and time. Change in Tc (ΔTc) was also compared between groups.

Results

ΔTc was significantly higher in TP vs. PP (p < 0.0001) and TP vs. AB (p < 0.0001) groups under C treatment. WS significantly attenuated ΔTc in TP (p = 0.001), but did not change ΔTc in PP or AB.

Conclusion

WS effectively attenuated Tc elevation during exercise in athletes with TP.

Sponsorship

Texas chapter of the Paralyzed Veterans of America.