Nieman 1990.

Methods	Study design: parallel‐group randomised controlled trial Location, number of centres: Loma Linda University Country: USA Study period: last weekend of January to mid‐May 1989 Methods of analysis: "all participants reported to the Loma Linda University Human performance Lab for testing at 0700 hours following 12 hours of fasting. After resting for at least 5 minutes, blood samples were collected. Participants returned throughout the day for assessment of the following: height and weight, body composition (hydrostatic weighing and 7‐site skinfold tests), resting 12‐lead EKG and 12‐lead EKG graded exercise testing with metabolic measurements. If a participant exhibited overt symptoms of URI, the appointment was rescheduled. Maximal graded exercise testing was conducted using the Bruce treadmill protocol on the Quinton 44000 stress test system and Q55 treadmill (Quinton Instrument Co., Seattle, WA). Metabolic measurements were taken with the Sensor Medics MMC Horizon System 4400 metabolic cart (Sensor Medics, Anaheim, CA). Log books for daily recording of health problems and exercise patterns were given to each subject at baseline. Heparinised whole blood was used for NK cell number and activity assays and EDTA whole blood for complete blood counts (CBC). CBC were performed on Coulter S‐Plus IV instrumentation with visual cell differentials in our clinical hematology laboratory" Statistical analysis: "results are expressed as mean ± SE. A 2 x 3 repeated measures ANOVA with 1 between‐participants factor (EX versus NEX) and 1 within‐participant factor (time of testing) was used to analyse the data. When Box's M suggested that the assumptions necessary for the univariate approach were not tenable, the multivariate approach to repeated measures ANOVA was used. In the latter case, Pillais trace statistic was used as the test statistic. With regard to comparison among specific means, only 7 comparisons were of interest to us. These were the contrast of the baseline measures with the 6th and 15th week measurements within the EX and NEX groups and the contrast between the EX and NEX groups at each of the 3 measurement points. The Dunn‐Sidak procedure was used to test these comparisons. Pearson correlations were used to determine the association between change in cardiorespiratory fitness, NK cell activity and URI symptomatology. Comparison between groups for age, BMI and URI were evaluated by simple univariate t‐tests"
Participants	Recruitment means: not stated Target participants: premenopausal woman N screened: 50 mildly obese premenopausal woman N completed: 36 completed: 18 (exercise) and 18 (control) Gender F = 36: placebo 18, exercise 18 Age: exercise 36.0 (1.6); control 32.8 (1.4) Inclusion criteria: "25 to 45 years of age, mildly obese (10% to 40% overweight), premenopausal, 155 cm to 170 cm in height, not presently on an exercise programme or a reducing diet, a non‐smoker without a history of alcohol or drug abuse, no current use of medications (except oral contraceptives), absence of hypertension and diabetes and no family history of heart disease" Baseline details: age, BMI, weight, compliance, NK cell response, metabolic parameters including HR, VE, and VO₂
Interventions	Setting of intervention: Loma Linda University Human Performance Lab Description of intervention: the EX group followed a closely supervised walking programme on a measured course consisting of 5, 45‐minute sessions each week for 15 weeks at an intensity of 60% of heart rate reserve. To ensure that participants exercised at a proper intensity, heart rates were monitored by checking pulse rates every 0.8 km. At the completion of 45 minutes the supervisor recorded participant's walking distance to the nearest 0.16 km. During the 15‐week study, the NEX group was instructed not to participate in any exercise outside of normal daily activity. Delivered by: supervised exercises Follow‐up period: 15 weeks Co‐interventions: the medication was kept constant during the study period
Outcomes	Number of days with ARI; symptoms days per URI; NK cell response, metabolic parameters Follow‐up period: 15 weeks
Notes	Study funding: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The authors do not explain how the random sequence was generated.
Allocation concealment (selection bias)	Unclear risk	There is no description of how allocation was concealed. "Those who qualified for the study were instructed that they would be randomly assigned to an exercise (EX) or non‐exercise (NEX) group"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were blinded to the study objectives, but lacked explanation on how they did it. Personnel were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcomes measured by participant self‐report.
Incomplete outcome data (attrition bias) All outcomes	High risk	Substantial loss to follow‐up: 28% dropouts, 8 at the beginning of the study and 6 during the study
Selective reporting (reporting bias)	Low risk	The outcomes prespecified in the methods were reported in the results.
Other bias	Low risk	The study seems to be free of other sources of bias.