Table 1.

Study characteristics to measure the effect of moderate intensity aerobic exercise on immune functions.

Study	Design	Sample size	Intervention type	Duration/Frequency of intervention	Major findings
Nieman et al 1993 [10]	RCT	55	Moderate intensity exercise, 60% HRR	30–40 min duration, 5 days/wk. for 12 wks.	NK activity, T cells functions improved with lower incidence of URTI in the exercise group
Nieman et al 1990 [11]	RCT	36	Moderate intensity exercise, 60% of HRR	45 min duration, 5 days/wk for 15 weeks	Reduction in URTI symptoms, increased NK cell activity
Chubak et al 2006 [12]	RCT	115	Moderate intensity exercise	45 min, 5 days/wk for 12 months	Risk of colds decreased in exercisers
Woods et al 2009 [13]	RCT	144	Moderate Intensity exercise, 60–70% maximal oxygen uptake	3 days/wk, and the duration of each session approximately 45–60 min for 10 months	Participants in the exercise group experienced improvements in influenza seroprotection throughout the entire influenza season, exercise group experienced reduced overall illness severity and sleep disturbance
Barrett 2012 [14]	RCT	154	Moderate-intensity sustained exercise, with a target rating of 12–16 points on the 6 to 20-point Borgs scale	120 min session/wk followed 45 min home exercise program for 8 weeks.	Reduced URTI episodes and severity of Illness
Sloan 2012 [15]	RCT	32	Exercise training was comprised of a 16-week, 5 days/week, home-based walking program. Each exercise session consisted of 30-min brisk walking at a prescribed moderate aerobic exercise intensity corresponding to 75% of individual age predicted Heart rate maximum	Exercise training comprised of a 16-week, 5 days/week, home-based walking program.Each exercise session consisted of 30-min brisk walking at a prescribed moderate aerobic exercise intensity corresponding to 75% of individual HR max	16-week moderate intense walking program can increase the secretion of salivary immunoglobulin A, which constitutes the main specific immune defense mechanism in saliva

URTI: Upper Respiratory Tract Infection, RCT: Randomized controlled Trial, HRR: Heart Rate Reserve, wk: Week, HR max: Heart Rate Maximum, Borgs Scale: Rating of Perceived Exertion, nk cells: natural killer cells.