Table 1 Characteristics and results of the included studies

 Hall, 2012 [22]

USA, Canada

6 times/wk., ≥6 h

RCT, CHD controls

12

52 ± 14

Short physical performance battery (SPPB), scale 1 to 12

Change SPPB score after 12 mo NHD: 8.1 ± 2.8 to 7.8 ± 3.4.

Adjusted mean change in 12 mo NHD: − 0.92 ± 0.44 vs control group: − 0.41 ± 0.43, p = 0.41.

 Chan, 2007 [29]

Canada

5–6 times/wk., 6–8 h

Prospective cohort, healthy controls

6

41 ± 3

Exercise duration in seconds and capacity expressed as % of the predicted VO_2peak

Change in exercise duration after 3–6 mo NHD: 617 ± 50 vs 682 ± 55, p = 0.03, VO_2peak: 66 ± 8 vs 75 ± 6, p = 0.05. Healthy controls at baseline: exc. Duration: 722 ± 53, VO_2peak: 90 ± 4.

 Eps, 2010 [24]

Australia

3–5 times/wk., 6–10 h

Prospective cohort, no controls

12

52 ± 13

6-min walk test (6MWT) in meters

Change 6MWT after 6 mo NHD: 513 m vs 536.5 m, p = 0.007.

 Kayson, 2012 [23]

USA, Canada

6 times/wk., ≥6 h

RCT, CHD controls

12

52 ± 14

Lean body mass (LBM) in kilograms by bioelectrical impedance analysis (BIA)

Mean change LBM after 12 mo NHD: 47.4 ± 12.5 to 48.2 ± 12.0.

Adjusted mean change in 12 mo NHD: − 0.49 ± 0.63 vs control group: − 0.04 ± 0.61, p = 0.61.

 Torigoe, 2016 [30]

Japan

3 times/wk., 8 h

Prospective cohort, CHD controls

2

45 ± 3

Skeletal muscle mass (SMM), lean body mass (LBM) in kilograms by BIA

Change in SMM after 2 mo NHD: 17 g increase. LBM: 20 g increase after 2 mo NHD, ‘significant’ (no p-value).

 Ipema, 2014 [28]

Netherlands

4–6 times/wk., 8 h

Prospective cohort, CHD controls

12

41 (36–51)

Fat-free mass (FFM) in kilograms by Dual-energy X-ray (DXA)

Change FFM after 12 mo NHD: 52.3 ± 8.3 to 50.9 ± 8.50, p = 0.095. Change control group: 53.5 ± 8.1 to 52.4 ± 7.6.

 Pellicano, 2010 [26]

Australia

3–5 times/wk., 8 h

Cross-sectional, matched, CHD controls

–

49 ± 11

SMM in kilograms by DXA

Change in SMM in NHD: 26.3 ± 4.16 vs control group: 25.6 ± 5.61, p = 0.65.