Cardiorespiratory fitness protects against dementia

In a large, prospective study, high cardiorespiratory fitness lowered the risk of developing Alzheimer’s disease (AD) and related disorders (ADRD). The association was inverse, independent, and graded: the highest-fit group had the lowest ADRD risk, the lowest-fit group the highest.

Cardiorespiratory fitness is associated with favourable health outcomes, but the impact on the risk of incident AD/ADRD is unknown [1]. This relationship was examined in 649,605 military veterans in the Veterans Health Administration database who completed a standardised exercise treadmill test between 2000 and 2017 and did not have ADRD at that time [2]. Participants were aged between 30 and 95 years (average age: 61 years); 5.7% were women and 16.6% African Americans. Based on peak metabolic equivalents (METs) during the first exercise treadmill test, they were differentiated into 5 age-specific fitness categories: lowest-fit (n=132,634; METs=3.8), low-fit (n=129,493; METs=5.8), moderate-fit (n=120,988; METs=7.5), fit (n=137,122; METs=9.2), and highest-fit (n=129,368, METs=11.7). The lowest-fit group was the reference to establishing hazard ratios for incident ADRD. The average follow-up was 8.8 years.

The results showed a strong, graded, inverse association between cardiorespiratory fitness and ADRD risk. Incident rates for ADRD were 9.5, 8.5, 7.4, 7.2 and 6.4 per 1,000 person-years in the low-fit, moderate-fit, high-fit, and highest-fit group, respectively (P<0.001). The adjusted HR for incident ADRD in respectively the lowest-fit to the highest-fit group were 0.87 (95% CI 0.85–0.90; P<0.001), 0.80 (95% CI 0.78–0.83; P<0.001), 0.74 (95% CI 0.72–0.76; P<0.001), and 0.67 (95% CI 0.65–0.70; P<0.001), respectively, compared with the lowest-fit group. A limitation of the study was that most participants were men and white.

“One exciting finding of this study is that as people’s fitness improved, their risk of AD decreased – it was not an all-or-nothing proposition,” said study author Dr Edward Zamrini (Washington DC VA Medical Center, DC, USA). “So people can work towards making incremental changes and improvements in their physical fitness, which will then hopefully be associated with a related decrease in their future risk of AD.”

1. Rolland Y, et al. Clin Geriatr Med. 2010;26(1):75–87.
2. Zamrini E, et al. Cardiorespiratory fitness is protective against Alzheimer’s and related disorders. S15.008, AAN 2022, 02–07 April, Seattle, USA.

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Posted on 2 June 202225 March 2024