Table 1.

Positive effects of exercise training and physical activity in colorectal cancer patients and animal models

Study	Sample size	Conditions	Type of exercise	Major finding	Refs.
Colbert (2001)	29,133 men	50–69 years old	occupational and leisure-time activities	findings provide further evidence of an inverse association between physical activity and colon cancer The relationship appeared to be stronger in the distal colon, rather than the proximal colon, and a similar association was seen for rectal cancer	[14]
Thune (2001)	40,674 patients	N/A	Occupational physical activity Leisure time physical activity	A dose–response effect of physical activity on colon cancer risk was especially observed	[15]
Chao (2004)	940 colon and 390 rectal cancer patients	Mean age of 63 years old	Recreational Physical Activity	Increasing amounts of time spent at recreational physical activity are associated with substantially lower risk of colon cancer Recreational physical activity is associated with lower risk of rectal cancer in older men and women	[16]
Calton (2006)	31,783 women	Mean age of 61 years old	Daily physical activity	Data do not support the hypothesis that physical activity is related to a lower incidence of colon cancer	[17]
Mai (2007)	120,147 participants	22–84 years old	Lifetime recreational physical activity	Lifetime recreational physical activity may protect against colon cancer among postmenopausal women who have never used hormone therapy Among hormone therapy users, who have lower risk of colon cancer, recreational physical activity does not seem to provide any additional benefit With declining rates of hormone therapy use, physical activity offers one possible means for reducing women's colon cancer risk	[18]
Coups (2008)	1932 respondents to the Health Information National Trends Survey	18–70 years old	Moderate-intensity activities	There is poor awareness among U.S. adults of the role that physical activity plays in preventing colon cancer	[19]
Wolin (2010)	158,253 participants	N/A	Regular long-term physical activity	Regular long-term physical activity was associated with a lower risk of colon cancer mortality	[20]
Boyle (2011)	870 cases	40–71 years old	Recreational Physical	Physical activity may have a greater effect on the risk of distal colon cancer than proximal colon cancer Vigorous physical activity is required to reduce colorectal cancer risk	[21]
Sanchez (2012)	548 patients	Mean age of 58 years old BMI of 27	Exercised for at least one hour per week	Exercise was an independent negative predictor for the presence of adenomas anywhere in the colon Patients who reported exercising one or more hours weekly had a lower prevalence of any polyps	[22]
Kuiper (2012)	1,339 participants	Mean age of 65 years	Recreational physical activity	Patients reporting activity levels ofC18 MET-h/week had significantly lower colorectal cancer-specific mortality	[23]
Weijenberg (2013)	120,852 participants	55–69 years old	Occupational physical activity	Regular long-term physical activity and fewer sitting hours may protect against colon cancer, particularly distal colon cancer	[24]
Moore (2016)	1.44 million participants	Median [range] age, 59 [19–98] years old	Leisure-time physical activity of a moderate to vigorous intensity	Leisure-time physical activity was associated with lower risks of colon cancer	[25]
Aleksandrova (2017)	519 978 participants	25–70 years old	High physical activity	Promoting physical activity, particularly outdoors could represent a promising strategy for colon cancer prevention	[26]
Mahmood (2018)	23,586 patients	27 to 76 years old	Recreational activity	Recreational activity was associated with reduced CRC risk. A non-significant, inverse association was observed for occupational activity, whereas no association was found for transport or household domains	[27]
Animal models
Baltgalvis (2009)	48 Apc(Min/ +) mice	Four-week-old male mice	Regular moderate-intensity treadmill exercise (18 m/min, 60 min/d, 6 d/wk)	The induction of adiposity, inflammation, and immunosuppression by the Western-style diet may compromise the beneficial effect of moderate-intensity exercise on the intestinal polyp burden in Apc(Min/ +) mice	[28]
Kelly (2017)	N/A	Eight-weeks of age male mice	Voluntary running wheel access	The results indicate that voluntary exercise should be used as a preventative measure to reduce risk for environmentally induced CRC with the realization that the extent of protection may depend on genetic background	[29]