Exercise and metabolic disease/prostate/Exercise Training

Many men suffering from prostate cancer are undergoing androgen deprivation therapy (ADT) to combat the cancer. This type of treatment has proven to be quite effective, but it is also associated with a number of side-effects. Some of these side-effects include an increased likelihood of osteoporosis, increased body fat and decreased lean body mass, sexual dysfunction and decreased quality of life. Exercise is becoming more and more recognised as an effective way of dealing with or slowing down these known side-effects. The goal of exercise for patients undergoing ADT is obviously to help improve their quality of life. There has been only a small amount of research on ADT and exercise. Most of this research focuses on resistance training, with a small amount dealing with combined aerobic and resistance exercise. Positive results have been seen in the small amount of research that has been conducted⁽²⁾, in regards to decreasing the side-effects of ADT. Below resistance training is discussed as an ADT intervention, as well as resistance training combined with aerobic training following that, then finally the benefits of exercise for ADT patients are summarised.

Resistance training

• Resistance training has been suggested as a possible intervention method for patients undergoing ADT partly for the positive effect it can have on the patients bone density, as ADT patients suffer from decreased bone mineral density and are at an increased risk of osteoporosis.

• There has not been a great amount of research conducted on resistance training for ADT patients, but from the little research that has been conducted some interesting and positive results have been seen. In a 12 week study conducted in 2003 fatigue and quality of life were assessed in patients undergoing ADT, this was then compared with an experimental group participating in resistance training. It was found that as a result of resistance training fatigue levels were decreased and quality of life was improved. While fatigue and quality of life are difficult things to measure, relying on self-reporting, significant differences were seen between the 2 groups.

• Similar results were seen in another study which assessed the effects of a 20 week resistance training exercise program on ADT patients. This study only had a small number of partcipants, that being 10, but significantly improved results were seen in relation to muscular strength, muscular endurance, the performance of functional tests and balance. Muscle thickness was also increased.

• In both of these studies no significant, positive changes in body composition were observed, but lean body mass was preserved in most cases along with no changes to fat mass. Also in both of these studies no adverse side-effects were seen as a result of resistance training.

• More research is required in this area but from these results it appears resistance training could be a very useful mechanism for maintining or improving quality of life in patients undegoing ADT. Future research with resistance training could look to examine the effects of someone participating in resistance training prior to undergoing ADT and also the long term effects that resistance training has on ADT side-effects.

Combined aerobic and resistance training

• Positive results were also seen in a study that examined the effects of a 12 week combined aerobic and resistance training program. Participants only took part in 2 combined aerobic and resistance sessions per week but still saw significant improvements in muscle mass, strength, physical function and balance. Improvements were also seen in relation to fatigue levels and general health, both of these outcome measures approached significance. Interestingly, similar results were seen compared to that of the studies that focused solely on resistance training when it came to body composition, with no significant changes in fat mass. But a significant increase in lean mass was observed, this was also similar to the results seen in the other studies dealing with resitance training. This suggests that it is possible to increase muscle size with depleted levels of testosterone.

• Another study also examined the effects of an exercise program that incorporated aerobic and resistance training. In this study participants were given a theory-based take home exercise program which advised them to exercise 3 to 5 times per week. In this case the resistance training portion of the program was only light. In the space of 12 weeks participants were able to significantly increase their functional capacity, based on the results of a 6 minute walk test. Distance covered increased while heart rate and perceived exerction decreased. This was coupled with fatigue levels improving and quality of life improvements approaching significance. A possible reason for quality of life changes not reaching significance could be due to the fact that some participants took part in far fewer training sessions than others, therefore not everyone gained the full benefits of the program.

• These results were supported in a similar study which examined a 16 week exercise program on ADT patients. The exercise program was very similar, mainly consisting of home based sessions made up of aerobic and light resistance exercises. Although this study had quite a high drop out rate, Significant positive changes were seen for girth measures and blood pressure, whilst depression and fatigue approached significant positive change.

• Similar to the resistance training studies, no adverse side-effects were seen due to increased exercise in any of these mentioned studies. There is currently no research on aerobic training as a stand alone method for improving quality of life for patients undergoing ADT, this is an area where future research could look to explore.

Exercise and ADT benefits

While further research is required, based on the research that has been conducted to date it appears that the approriate exercise can lead to prostate cancer patients suffering significantly decreased side-effects from ADT and therefore enjoying an improved quality of life. The benefits of exercise for ADT patients are summarized below:

• Increased bone mineral density⁽²⁾
• Decreased fatigue levels⁽⁴⁾⁽⁷⁾
• Increased muscular strength⁽⁵⁾
• Increased muscular endurance⁽⁵⁾
• Increased physical functioning⁽⁷⁾⁽⁵⁾
• Improved balance⁽⁶⁾
• Increased muscle thickness⁽⁵⁾⁽⁶⁾
• Increased cardiac endurance⁽⁷⁾
• Lean body mass preserved or increased^(6)(5)(4)
• Fat mass stops increasing^(6)(5)(4)
• Improved general health⁽⁶⁾
• Decreased girth measures⁽⁸⁾
• Decreased blood pressure⁽⁸⁾
• Decreased symptoms of depression⁽⁸⁾