The COVID-19 outbreak limits physical activities and increases sedentary behavior: A possible secondary public health crisis for the elderly.

In February 2020, the Japanese government requested the general population to avoid unnecessary outings, as well as local governments, to close schools nationwide to prevent coronavirus disease 2019 (COVID-19) from rapidly spreading [1]. Although these measures are indispensable to prevent the spread of the highly contagious disease, refraining from outings for prolonged periods could cause unintended negative consequences on health, especially in the elderly, due to reduced physical activity and sedentary behavior at home.

In the Great East Japan Earthquakes in 2011, up to 60% of the elderly in shelters reportedly experienced disuse syndrome one month after the disaster [2], indicating vulnerability to confinement. Although this may be an extreme example, even moderate restraint on outings could result in decreased physical activity and increased sedentary behaviors, which may contribute to aggravating pre-existing chronic diseases, accelerating frailty or locomotive syndrome,1 and increasing long-term morbidity and mortality among the elderly [3].

We conducted an emergent nationwide internet survey among 5000 people aged over 20 years old (including 1000 people over 60 years old) to assess the physical activities and sedentary behaviors in Japan during February 2020 [4]. The participants were informed and gave consent that data from the study would be released to public or submitted for publication, when they participated in this study. This study was approved by the institutional review board of the authors’ affiliated institution.

Overall, 48% and 38% of people over the age of 60 had less physical activity and longer sedentary time, respectively, when compared to those over the same period in the previous year (Table 1 ), which percentages were the highest among all age groups both in men and women. Additionally, the instrumental activities of daily living were affected during the COVID-19 outbreak. Overall, 52% and 43% of individuals over the age of 60 with decreased outings reported a lower frequency of shopping and the use of public transportation, respectively. We consider that many more people experienced further decreased physical activitiy and increased sedentary time after this survey in February, since the Japanese government announced a state of emergency and strongly requested the people to self-quarantine in April.

Table 1

Frequency of outings, physical activities, and sedentary time during February 2020, compared to the same period of the previous year.

Age strata (y)	n	Q1. Frequency of outings (%)			P-value	Q2. Physical activities (%)			P-value	Q3. Sedentary time (%)			P-value
		Decrease	No change	Increase		Decrease	No change	Increase		Decrease	No change	Increase
Men					P < 0.001				P < 0.001				P < 0.001
20-29	500	43.2	40.6	16.2		36.0	53.4	10.6		18.6	54.4	27.0
30-39	500	47.2	44.0	8.8		40.2	52.0	7.8		14.8	53.6	31.6
40-49	500	45.2	50.4	4.4		32.8	61.8	5.4		7.6	64.8	27.6
50-59	500	47.6	48.0	4.4		33.4	62.0	4.6		6.2	67.4	26.4
60≥	500	54.2	41.6	4.2		43.6	52.8	3.6		6.4	57.2	36.4
Women					P < 0.001				P < 0.001				P < 0.001
20-29	500	51.6	34.6	13.8		38.6	49.4	12.0		15.8	49.4	34.8
30-39	500	61.2	32.8	6.0		44.8	50.2	5.0		13.0	49.2	37.8
40-49	500	57.0	38.8	4.2		39.6	55.8	4.6		8.6	58.0	33.4
50-59	500	56.2	39.8	4.0		41.4	54.4	4.2		8.2	58.8	33.0
60≥	500	62.6	32.6	4.8		52.8	43.0	4.2		8.4	52.0	39.6
Total	0	52.6	40.3	7.1		40.3	53.5	6.2		10.8	56.5	32.8

Q1. Are there any changes in the frequency of outings in the recent month compared to the same period of last year?

Q2. Are there any changes in physical activities in the past month compared to the same period of last year?

Q3. Are there any changes in sedentary time in the recent month compared to the same period of last year?

P-values are obtained from the chi-square test (<0.05 significant).

The COVID-19 pandemic will be expected to last for one or two years [5], and consequently, the elderly would be most likely to go on self-quarantine for the corresponding period, as this survey indicated. However, it also means that the elderly could be more vulnerable through decreased physical activity and increased sedentary behavior. Moreover, it is expected that once health conditions are impaired in the elderly, recovery to the original health status can be challenging, given the declined intrinsic capacity [6]. Therefore, the government, municipalities, and non-governmental organizations, should cooperate and take necessary measures to avoid this potentially critical public health problem, less physical activity and more sedentary behavior in the elderly during the COVID-19 pandemic. Suggestions include promotion with broadcast media, online workout programs, or distributing brochures to encourage at-home physical activities. We would have to create flexible design of the system to promote physical activities at home for the elderly.

Countries with a large aging population such as Japan need to tackle this problem to decrease the number of elderly with worsening health status during the pandemic owing to at-home confinement.

Author's contributions

KY, SY, KS, TF and TO conceived and designed the study. SY and TO performed the data collection. KY, SY and TO analyzed the data. KY wrote the initial draft of the paper. KY, SY, KS, TF and TO participated in interpretation of the data and revised the manuscript for important intellectual content. All authors read and approved the final manuscript.

Declaration of competing interest

We declare no competing interests. This study was funded by the ‘Locomo Challenge!’ Council, Tokyo, Japan. The Locomo Challenge! Council is a non-profit organization launched by the Japanese Orthopaedic Association, to educate the public about the importance of maintaining adequate mobility in their lives in a super-aging Japanese society.