Table 2.

Summary of case-control (CC) and longitudinal (L) studies on PA and TL.

Author, Reference	Year	Type	Participants	TL Measurements	Tissue for TL Analysis	Exposure Assessment Methods	Results
Colon et al. [81]	2019	CC	7 male triathlon athletes and 7 active controls	PCR	Blood	PA assessed by questionnaires and VO2max	The triathlete subjects had longer telomeres than the active controls. Positive association between TL and VO2max
Denham et al. [27]	2016	CC	Polish endurance athletes (n = 61) and paired active controls (n = 61)	PCR GE	Blood	PA reported by questionnaires	Endurance athletes have longer TL, as well as a higher expression of TERT mRNA
Denham et al. [82]	2013	CC	67 male ultramarathon runners and 63 controls	PCR	Blood	PA assessed by questionnaires	Ultramarathon runners had telomeres 11% longer than controls
LaRocca et al. [83]	2010	CC	57 participants: differing by age and PA	SB	Blood	PA assessed by questionnaires and VO2max	TL of the older endurance-trained adults was greater than their sedentary peers. TL was positively related to VO2max
Magi et al. [84]	2018	CC	26 men (20–50 y)	SB	Muscle	PA reported by interview	Regular physical training was positively with the maintenance of TL
Mathur et al. [85]	2013	CC	17 marathon runners and 15 controls	FISH	Blood	Different tests were performed	No differences were observed in the TL of the different PA groups or tests
Muniesa et al. [86]	2017	CC	125 young elite athletes	PCR	Blood	PA reported through a database	Elite athletes had a TL 12.4% longer than controls
Osthus et al. [87]	2012	CC	10 young and 10 elderlies (50% endurance athletes, 50% medium level)	PCR	Muscle	PA assessed by questionnaires and VO2max	Older endurance athletes had longer TLs compared to their counterparts. These differences were not seen in the young participants
Puterman et al. [88]	2010	CC	63 postmenopausal women	PCR	Blood	PA assessed by questionnaires	No association between PA and TL was observed. However, vigorous PA was linked to TL
Rae et al. [89]	2010	CC	18 endurance runners vs. 19 controls	SB	Muscle	PA assessed by questionnaires	No significant differences were found between the mean and minimum TL between the endurance runners and controls
Simoes et al. [90]	2017	CC	Elite sprinters (n = 11) and untrained controls	PCR	Blood	PA reported by medical history	Elite sprinters have longer TL than their paired controls
Soares-Miranda et al. [91]	2015	L	582 elderly subjects from CHS	SB	Blood	PA assessed by questionnaires and different tests	At baseline, higher PA was associated with longer TL. Prospective analyses show that changes in PA were associated with differences in changes in TL
Stenbäck et al. [92]	2019	L	700 elderly subjects (Finland)	PCR	Blood	PA assessed by questionnaires and accelerometry	PA for 2-w was not associated with TL after adjustment. However, moderate PA was associated with longest TL
Weischer et al. [93]	2014	L	4576 participants from CCHS	PCR	Blood	PA assessed by questionnaires	Increased PA was associated with short TL at baseline, but not with a change in TL during 10 years of follow-up

TL: telomere length; bp: base pairs; PA: physical activity; y: years old; TV: television; h: hour; d: day; w: week; m: month; y: year; VO₂max: maximal oxygen uptake; T2D: type 2 diabetes; PCR: Polymerase Chain Reaction; SB: Southern blot analysis of terminal restriction fragment lengths (TRF); GE: gene expression; TERT: telomerase reverse transcriptase gene; WB: Western blotting; CCHS: Copenhagen City Heart Study; HRS: Health and Retirement Study; CHS: Cardiovascular Health Study.