Effect of ageing on hypoxic exercise cardiorespiratory, muscle and cerebral oxygenation responses in healthy humans

Abstract

What is the central question of this study? This study aimed to determine the effect of ageing on cardiorespiratory and tissue oxygenation responses to hypoxia during maximal incremental exercise. What is the main finding and its importance? Older healthy subjects had preserved hypoxic cardiorespiratory and tissue oxygenation responses at rest and during moderate exercise. At maximal exercise, they had a reduced hypoxic ventilatory response but similar maximal power output reduction compared with young individuals. This study suggests that until moderate exercise, hypoxic responses are preserved until the age of 70 years and therefore that ageing is not a contraindication for high-altitude sojourn. This study assessed the effects of ageing on cardiorespiratory and tissue oxygenation responses to hypoxia both at rest and during incremental maximal exercise. Sixteen young (20-30 years old) and 15 older healthy subjects (60-70 years old) performed two maximal incremental cycling tests in normoxia and hypoxia (inspiratory oxygen fraction 12%). Cardiorespiratory responses, prefrontal cortex and quadriceps tissue oxygenation (near-infrared spectroscopy) were measured during exercise as well as during hypercapnia at rest. The hypoxic ventilatory response was similar in young compared with older individuals at rest and during moderate-intensity exercise (50% maximal power output: young 0.9 ± 0.2 versus older 1.1 ± 0.8 l min % ; P > 0.05) but larger in young subjects during high-intensity exercise (maximal power output: 2.2 ± 0.8 versus 1.8 ± 1.1 l min % ; P < 0.05). The hypoxic cardiac response did not differ between groups both at rest and during exercise. During exercise in hypoxia, young subjects showed greater deoxygenation than older subjects, at both the prefrontal cortex and quadriceps levels. The hypoxia-induced reduction in maximal power output (young -32 ± 5% versus older -30 ± 6%; P > 0.05) and the hypercapnic responses did not differ between groups. Older healthy and active individuals below the age of 70 years have cardiorespiratory and tissue oxygenation responses to hypoxia similar to young individuals both at rest and during moderate-intensity exercise. Despite a lower hypoxic ventilatory response at maximal exercise, older individuals have similar oxygen desaturation and maximal power output reduction compared with young subjects.

Limitation of Maximal Heart Rate in Hypoxia: Mechanisms and Clinical Importance

“…Most of the studies involved healthy young adults (between 20 and 39 years old as shown in Figure 4 ). Obviously, the general trends show a progressive decrease in HR max with altitude whatever the age groups, without marked differences (Puthon et al, 2017 ). A trend toward a slightly greater decrease is observed in 30-39 years vs. 20-29 years.…”

“…In Figure 4 , 14-19 years and 50-59 years age groups show different behaviors than 20–29 years and 30–39 years age groups, but likely due to small sample sizes and to the fact that for these ages groups, participants were patients for whom only few data are available (Supplementary Table S1 ). Hence, if HR max decreases with age (Lhuissier et al, 2012 ), age per se does not seem to alter the decrement in HR max with acute hypoxia (Puthon et al, 2017 ), but this needs to be confirmed by specifically designed studies. It also suggests that the hypoxia effects will be relatively greater for an older subject compared to a younger one.…”

Twelve weeks of exercise modality in hypoxia enhances health‐related function in obese older Korean men: A randomized controlled trial

“…However, the majority of studies on obesity and aging have mainly been carried out in Western society, and studies using hypoxic therapy for health promotion of the older adult population are very limited. 3,[14][15][16][17][18] Until now, the majority of obese and aging studies have focused on abdominal or central obesity, hypertension, insulin resistance, high triglyceride and low high-density lipoprotein cholesterol levels, which are associated with metabolic syndrome. 6 The numerous changes in health-related factors that occur during the process of obesity and aging need to be investigated.…”

Respiratory‐related cortical activity in patients with COPD and aged normal individuals: towards a different vision of dyspnoea?

“…Indeed, recently published data suggest that the ventilatory response to hypoxia and hypercapnia at rest and during sub‐maximal effort in elderly subjects (mean age of 66 years) is normal (Puthon et al . ). The automatic ventilatory drive has never been studied in older subjects.…”

“…It should also be emphasised that their hypothesis that the reduction in the automatic neural drive to breathe is linked to ageing requires more evidence. Indeed, recently published data suggest that the ventilatory response to hypoxia and hypercapnia at rest and during sub-maximal effort in elderly subjects (mean age of 66 years) is normal (Puthon et al 2017). The automatic ventilatory drive has never been studied in older subjects.…”