Resting heart rate is a population-level biomarker of cardiorespiratory fitness: The Fenland Study

Abstract

Introduction Few large studies have evaluated the relationship between resting heart rate (RHR) and cardiorespiratory fitness. Here we examine cross-sectional and longitudinal relationships between RHR and fitness, explore factors that influence these relationships, and demonstrate the utility of RHR for remote population monitoring. Methods In cross-sectional analyses (The UK Fenland Study: 5,722 women, 5,143 men, aged 29-65y), we measured RHR (beats per min, bpm) while seated, supine, and during sleep. Fitness was estimated as maximal oxygen consumption (ml⋅min-1⋅kg-1) from an exercise test. Associations between RHR and fitness were evaluated while adjusting for age, sex, adiposity, and physical activity. In longitudinal analyses (6,589 participant subsample), we re-assessed RHR and fitness after a median of 6 years and evaluated the association between within-person change in RHR and fitness. During the coronavirus disease-2019 pandemic, we used a smartphone application to remotely and serially measure RHR (1,914 participant subsample, August 2020 to April 2021) and examined differences in RHR dynamics by pre-pandemic fitness level. Results Mean RHR while seated, supine, and during sleep was 67, 64, and 57 bpm. Age-adjusted associations (beta coefficients) between RHR and fitness were -0.26, -0.29, and -0.21 ml⋅kg-1⋅beat-1 in women and -0.27, -0.31, and -0.19 ml⋅kg-1⋅beat-1 in men. Adjustment for adiposity and physical activity attenuated the RHR-to-fitness relationship by 10% and 50%, respectively. Longitudinally, a 1-bpm increase in supine RHR was associated with a 0.23 ml⋅min-1⋅kg-1 decrease in fitness. During the pandemic, RHR increased in those with low pre-pandemic fitness but was stable in others. Conclusions RHR is a valid population-level biomarker of cardiorespiratory fitness. Physical activity and adiposity attenuate the relationship between RHR and fitness.

Causal associations between cardiorespiratory fitness and type 2 diabetes

“…Resting heart rate is inversely correlated with fitness in observational studies and decreases as a response to aerobic exercise training 2 , 22 – 25 . We hypothesised that resting heart rate could also be used as a viable proxy trait for fitness in a genetic framework and conducted several analyses to test this.…”

Establishment of a Predictive Model for Acute Respiratory Distress Syndrome in Patients with Bacterial Pneumonia

“…The heart rate could reflect respiratory function, cardiac function and immune response. [24][25][26][27][28] Several studies showed that the heart rate could be exploited for the early identification of infections and respiratory diseases. 29,30 The vagus nerve was an important neuroimmunomodulator in the inflammatory pathway, and heart rate could reflect the function of the vagus nerve.…”

Concurrent Validity of Four Activity Monitors in Older Adults

“…The demographics of the participants are reported in Table 1 and include age (years), sex (female/male), body height (to the nearest 0.1 cm; barefoot), body mass (to the nearest 0.1 kg; barefoot and light clothing only), body mass index (calculated by dividing body mass by squared body height (kg•m −2 )), then following a 20 min seated posture, resting oxygen consumption (RVO 2 ; mL•kg −1 •min −1 ; standard temperature and dry gas at standard barometric pressure; assessed while sitting quietly on a chair for four minutes (as this time frame does not affect the accuracy of energy expenditure measurements [27])), and resting heart rate (beats per minute) as a proxy for physical fitness levels [28], except for participants who used heart rate controlling medication. The self-selected walking speed on a treadmill was referred to as preferred walking speed (km•h −1 ).…”