Individuals experiencing long COVID frequently report persistent fatigue and other symptoms that significantly impact their quality of life.
A recent investigation published in JACC: Advances revealed that people with a higher number of long COVID symptoms exhibited reduced physical activity and poorer cardiovascular health indicators. However, further research is necessary to fully understand the interplay between activity levels and cardiovascular disease (CVD) in this population.
The researchers noted that the findings "demonstrate associations between a high burden of persistent long COVID symptoms and objective indicators of impaired cardiopulmonary fitness." They emphasized the need for "Additional research, including those employing longitudinal designs, is needed to determine if long COVID at least six months after SARS-CoV-2 infection is a novel risk factor for cardiopulmonary disease."
Reduced Heart Rate Variability and Increased Resting Heart Rate Observed
The study analyzed six months of data from wearable activity trackers for 1,475 participants in the Researching COVID-19 to Enhance Recovery Adult Cohort Study (RECOVER). This evaluation focused on specific cardiovascular health metrics, including heart rate variability, resting heart rate, heart rate during exercise, overall activity levels, and step counts.
While previous studies have examined wearable data around six months post-COVID, this research looked at data from participants an average of 21 months after infection to assess the longer-term effects of long COVID on cardiopulmonary fitness.
The majority of participants were female (76%), White (65%), and either overweight or obese (70%). Most participants (66%) reported a low symptom burden, as defined by the 2024 Long COVID Research Index (LCRI).
Conversely, individuals with a higher symptom burden (34%) took fewer steps daily, were less active, and engaged in more sedentary behavior compared to those with fewer symptoms. Those with more symptoms also showed "significantly lower" heart rate variability (HRV) and higher resting heart rates. Both lower HRV and elevated resting heart rates have been associated with an increased risk of CVD and mortality.
The authors explained that in the context of long COVID, prior research suggests that reduced cardiopulmonary fitness and activity levels likely stem from a combination of limited exercise capacity and a conscious effort to avoid postexertional malaise, rather than a lack of motivation.
They acknowledged that their "wearable sensor data cannot definitely disentangle the effects of physiologic impairment (eg, ventilatory, circulatory, and neuromuscular limitations) vs intentional effort restriction on the cardiopulmonary fitness among participants."
Existing research has already established a link between long COVID and CVD. An analysis published in Clinical Medicine Insights: Cardiology found that 11.9% of patients with long COVID developed CVD, compared to 6.8% of individuals without long COVID. A separate study from Sweden earlier this year also indicated a connection between a long COVID diagnosis and cardiovascular events, such as arrhythmias and coronary artery disease.
The researchers behind this latest study strongly advocate for further investigation into the relationship between physical activity and CVD in individuals with long COVID. They concluded that "Longitudinal analyses of physical activity with long-term follow-up are needed to evaluate whether the indicators of cardiovascular fitness and decreases in physical activity translate into an increased risk of cardiovascular disease."