Lockdown, slow down: impact of the COVID-19 pandemic on physical activity—an observational study

Background

The COVID-19 pandemic brought restrictions on the daily lives of the global population. For at least the initial phase, the UK population was advised to isolate at home, an unprecedented public health message. Although survey data suggest a mixed response by the general population,1 2 the effect of the ‘lockdown’ instruction on physical activity (PA) has yet to be objectively quantified. Focusing on people living with heart failure (HF), given contemporary health advice for managing stable HF in the community typically includes regular PA as part of a healthy lifestyle,3 any significant drop may have negative health consequences for these patients.

Modern cardiac implantable electronic devices (CIEDs) have multiple built in sensors which allow them to monitor a wide range of physiological parameters, including PA levels, continuously and automatically. When paired with home monitoring, these data can be monitored by clinical teams.4

Aims

Using activity data collected from CIEDs 4 weeks before and after the imposition of strict COVID-19 lockdown measures as part of the ongoing prospective Triage-HF Plus Evaluation (Triage-HF Plus), we aim to quantify behavioural changes in activity in a cohort of CIED patients with HF.

Methods

The Triage-HF Plus study is a prospective observational study involving three hospital sites in North West England, UK. Briefly, Triage-HF Plus is a telephone-based clinical care pathway which uses remote monitoring data from CIEDs (Medtronic Triage Heart Failure Risk Status (HFRS)) to identify patients at increased risk of decompensated HF.5 The aim of the study is to evaluate workforce burden and healthcare utilisation associated with the pathway. Recruitment began on 6 September 2019 and remains ongoing. Inclusion criteria include: over 18 years, HFRS compatible CIED in situ, able to comply with remote monitoring and follow-up.

Daily activity data are collected as part of the HFRS, measured by an accelerometer within the CIED, and stored as time ‘active’ per day based on an accelerometer count threshold.6 7 For this evaluation, activity data were available as ‘total minutes active per week’. We extracted data for the 4 weeks preceding and following the formal announcement of strict national lockdown measures in England on the evening of 23 March 2020. Prior to this announcement, life continued largely as normal until 16 March when the prime minister announced advice to ‘stop non-essential contact with others and to stop all unnecessary travel’,8 however, due to ‘panic buying’ and uncertainty, it is generally accepted that strict ‘lockdown’ started in the UK after 23 March. In England, government guidance was to remain at home unless required to go outdoors for a list of very limited reasons (essential work, shopping for necessities as infrequently as possible, medical or care reasons, or a short (maximum 60 min) daily period of exercise).9 10 This advice did not significantly change in the 4 weeks following the announcement.

Analysis was performed on Microsoft Excel 2019 and R software (V.4.0.2, 2020). Only participants with complete activity data for all 8 weeks studied were included. Statistical tests employed include paired t-test, paired Wilcoxon-test, Welsh two sample t-test (when Bartlett test significant for homogeneity of variance), analysis of covariance (ANCOVA) for multiple categorical variables, and Pearson/Spearman’s rank correlation (for continuous variables). A p value <0.05 was considered significant, where MD denotes difference in means.

Results

At the time of data retrieval, demographic and clinical data were available for 414 patients, of which 8 weeks of complete activity data were available for 311 patients (75.1%). An overview of the studied population is shown in table 1.

Of note, the majority of the studied population (77.2%) were men, with 56% over 70 years of age. Most had a high body mass index (BMI) (77% over 25). Two hundred and eighty-three (92.2%) patients had established HF, with 52.2% NYHA (New York Heart Association) class II. The majority were fitted with a cardiac resynchronisation device with defibrillator. Comorbidities included: diabetes (73.3%), ischaemic heart disease (52.1%), hypertension (45.6%), atrial fibrillation (44.6%), chronic kidney disease (42.1%) and frailty (55.9%, defined as a PRISMA-7 score ≥3).11

79.1% (246) of the cohort had a reduction in activity post-lockdown. Median activity per day in the 4 weeks pre-lockdown was 134.7 min/day (min/day) compared with 113.9 min/day in the 4 weeks post-lockdown. Post-lockdown there was a significant reduction in activity (p<0.001), equating to a reduction of 20.8 active min/day.

This reduction was uniform across the cohort (as demonstrated in figures 1 and 2), with subgroup analyses demonstrating a small but significantly more pronounced drop in activity for females (MD=6.2, 95% CI 0.1 to 12.3, p=0.04), but no statistically significant difference with respect to age (Spearman’s r=0.03, p=0.57), BMI (Spearman’s r=−0.09, p=0.11), frailty (MD=0.9, 95% CI −4.4 to 6.3, p=0.7), or device type (MD=5.5, 95% CI −13.1 to 2.1, p=0.16). A consistent pattern of activity across the 8 weeks studied emerged (see figure 1). PA was largely static leading up to lockdown implementation, followed by a precipitous drop in the 2 weeks post-lockdown. In the third and fourth week post-lockdown, there was a steady increase in observed activity, but this did not generally return to pre-lockdown levels (median activity week-1 138.6 min/day vs mean activity week-8 118.9 min/day, p≤0.001).

An exploratory analysis of the 65 (20.9%) patients whose total activity levels did not decrease post-lockdown found there was no significant difference in pre-lockdown activity (3839 median min active vs 3839.0 min active, p=0.62), or proportion of patients in the first or last quartile of pre-lockdown activity (first 29.2% vs 24.0%, last 27.7% vs 24.0%, p=0.48). There was no significant difference in demographics or comorbidities (as listed in table 1) between the two groups.

Conclusion

This is the first study quantifying the behavioural effects of the public health lockdown instructions using a study cohort of HF CIED patients undergoing objective daily activity monitoring as part of clinical remote monitoring. Our results show that activity dropped significantly during lockdown across all groups by approximately 20 min/day, with a trend to return to prior levels of activity by week three/four post initial lockdown measures. Twenty per cent of the cohort did not reduce their levels of activity. Exploratory analysis of this subgroup did not reveal any clear distinguishing characteristics, and similar NYHA score, frailty and pre-lockdown activity levels would suggest these are patients with matched functional status. Longer follow-up is required to establish if this is a sustained picture.

While other studies have reported reduced PA levels associated with global lockdown (by way of survey, mobile phone data and wearable devices12–15) this is the first report using a Medicines and Healthcare products Regulatory Agency/European Medicines Agency approved implanted device in an HF population. Furthermore, the demographic data recorded as part of this clinical study allows us examine the impact of key clinical characteristics on activity—a limitation of previous reports on lockdown activity.

This study demonstrates a rapid, quantifiable, negative effect on PA regardless of age, gender, BMI or frailty status—something perhaps never seen before in this generation. Further follow-up is required to establish if this change is sustained, or whether patients will adapt to keep active by other means or return to prior levels of activity in the long-term. Multiple studies have demonstrated a positive correlation between activity and overall health, and particularly for an older population with HF and/or frailty.16–18 Even short periods of sedentary behaviour can result in muscle wasting and functional decline.19 The long-term consequences of reduced activity in this population is unclear. As we prepare for a second, and possibly recurrent waves of infection in the absence of an effective vaccine, the risk/benefit discussion surrounding stringent lockdown and shielding measures for high-risk groups should consider these implications which may be possible to mitigate with regular exercise programmes, for example.

This study was limited to a predetermined cohort with data for the 4 weeks before and after lockdown making it difficult to extrapolate and predict the long-standing, clinically relevant adverse effect of this reduction in activity. The way in which activity is captured by the device is limited in two major ways: first PA below the device threshold would not be stored by the device, and second static exercise (such as an exercise bike) would not reliably trigger the accelerometer. Although evidence suggests device accelerometery strongly correlates with activity as measured by external monitors for the majority of HF patients,20 these limitations are pertinent when considering patients may switch to home gym equipment in response to the restrictions.

Finally, the study participants of the Triage-HF Plus study were largely of white British ethnicity (83.8%). The generalisability of our results to the UK broader population is of interest, but beyond the scope of this report.

In conclusion, in a UK population of HF patients with compatible cardiac devices undergoing remote monitoring, PA reduced by approximately 20 min/day in the immediate aftermath of strict COVID-19 lockdown measures.