Physical Activity and Breast Cancer
Thune et al (1997) found in their study of over 25,000 participants that an increased amount of physical activity during leisure time and work is associated with a decreased risk of breast cancer. The study evaluated the influence of physical activity, both at work and leisure time, in a large sample (n =25, 624, age 20 to 54) of pre-menopausal and post-menopausal women. Further support to the notion of increased physical activity and lower incidence of breast cancer is supported in studies of former college athletes10,11 and general population (Friedenreich et.al.,1995). One hypothesis for the lower incidence of breast cancer in former athletes relates to the later age of menarche usually found in this population (Frisch et al. 1985). Both early menarche and late menopause would be expected because they (the athletic population) would generally carry less body fat.
However, there are a number of studies that have found no evidence to suggest physical activity can help to reduce the incidence of breast cancer in a population. One such study looked at a large sample (n = 10118) of female teachers in Finland (Pukkala, et.al.,1993) and compared the incidence of cancers in a group of physically active teachers (PE teachers) with a less active group (language teachers). Another study showed that the risk for male and female breast cancer became elevated after socio-economic status was taken into consideration (Dosemeci et al 1993). A suggestion may be that lower socio-economic groups may not have sufficient physical activity and consume a “less healthy” diet (i.e., with higher fat intake), thus potentially increasing the risk of cancer. This article on the BBC website provides an interesting discussion on possible lifestyle links to breast cancer: http://news.bbc.co.uk/1/hi/health/1633831.stm .
A review by Van Gaal and Mertens, cited in
Kopelman and Stock (1998), shows conflicting evidence in relation to breast
cancer and fat distribution. Some studies have reported a correlation between
breast cancer risk and fat distribution (Van Gaal et al. (1998). Other studies
have not come to the same conclusions.
The connection between physical activity and body fat distribution is that physical activity can help control body weight.
Physical Activity and Colon Cancer
Much of the research conducted on cancer and physical activity combine the data for colon and rectal cancers. Friendreich and Orenstein (2002) state that the evidence for a link between physical inactivity and the appearance of colon cancer is strong and consistent. Giovanucci et al (1995) found that physical activity was inversely related with colon cancer, after adjustments for age and other factors.
Waist to hip ratio and waist circumference were also indicative of risk factors for colon cancer. Therefore, it could be hypothesized that increased abdominal adiposity is associated with an elevated risk. This can be viewed as a significant finding as the study examined a large group of participants (n = 51529). However, because the sample group consisted of health professionals, it is could be argued that this is not representative of the general population. Dosemeci et al. (1993) suggested that the lower the socio-economic status, the higher the incidence of colon cancer. Additionally cancers of the colon and prostate showed an increased risk with males participating in lower levels of activity. Slattery et al. (1997) lend support to the notion that low levels of physical activity and high energy intake (therefore, a potential increase in body mass) are associated with colon cancer. The same study found that a high level of energy intake that was balanced by a high level of physical revealed a non-significant risk of colon cancer.
Another study (Paffenbarger et al. 1987) highlighted varying populations, (i.e., dockworkers, college alumni etc.) and reviewed them for the incidence of cancer in relation to the levels of physical activity involved during both leisure time and occupational time. The conclusions suggested that the more active men have an increased likelihood to die from pancreatic and colorectal cancers. No differences by activity for the incident of prostate cancer were noted. However, Friedenreich (2001) suggests that the evidence for correlation between physical activity and colon/colorectal cancer is convincing. A significant number of studies have clearly demonstrated a large reduction in risk of cancer in the physically active. (Thun et al. 1992: Paffenbarger et al. 1987: Lee et al.1994)Batty and Thune (2000) suggest plausible mechanisms of protection of physical activity on insulin amongst others, which positively influence cells in the colon. Additionally, they suggest that physical activity improves the transit time of the bowel, thus reducing the contact time with carcinogens in faecal matter. The authors report the appearance of an increased risk of colon cancer associated with sedentary or light physical activity. This supports the statement that increased physical activity appears to aid in the reduction of risk for colon and rectal cancers.
Other Cancer Sites
An examination of data from the National Health and
Nutrition Examination Survey (NHAMES 1) by Albanes et al. (1989) showed a
nearly two-fold risk increase in the inactive group for all cancer sites. The
study used 5,138 men and 7,407 females, age 25 to 74 years of age. The most
common sites of cancer identified in the follow up period of the study for
males were lung, prostate and colorectal. The common sites in females were
identified as breast and colorectal.
Exercise has an important role in cancer prevention by helping to maintain a healthy body weight especially when combined with a healthy diet. It may also have a more direct effect on cancer risk. Exercise is thought to influence the levels of hormones such as estrogen and insulin in the body and may have a particular effect in hormone-related cancers.
There is also evidence that physical activity significantly reduces the risk of bowel cancer and may help lower the risk of breast, prostate, lung and endometrial cancer. Cancer Research UK suggests moderate exercise five days per week for around thirty minutes.
The protective mechanism suggested by Thune and Furberg (2001) is that physical activity improves ventilation and perfusion. Therefore, concentration of carcinogenic agents in the airways will be reduced as will the duration of agent/airway interaction. Albanes et al. (1989) supports a protective effect from leisure time activity and is supported by Lee et al. (1999) and Severson et al (1989). Due to the relatively small number of supportive studies on lung cancer and physical activity, the current results must be treated with caution, particularly when considering the participants of the studies. The majority of participants in this area have been male, so perhaps more females need to be recruited to establish a male/female risk factor. There is little mention of the ethnicity of the participants.
Exercise prescription as part of the disease management for cancer patients must be highly individualized because of the extreme variability of the effects of cancer and treatment regimens on functional capacity. Furthermore, other concurrent or prior health problems should be anticipated and taken into account in developing any exercise prescription. Although it is acknowledged that the recommendations for exercise should be modified for specific patients, it is generally accepted to recommend 30 minutes of continuous exercise such as brisk walking or swimming three to four times per week. Attention should be given to safety measures and general health maintenance. These guidelines are the general exercise recommendations outlined by American College of Sports Medicine (2006) and more recently updated (Haskell, et al. 2007). Furthermore, Cancer UK published a good healthy living leaflet for general health ( http://info.cancerresearchuk.org/healthyliving/tentoptips/ ).Walking and cycling are recommended as safe and generally well tolerated exercise modes involving large muscle groups. De-conditioned patients should begin with daily sessions of shorter duration and lower intensity. In general, moderate intensity exercise (50-75% HR reserve, RPE 11-14) sessions of between 20 and 30 minutes duration are recommended, with modifications as needed, including an interval approach to cardiovascular exercise, consisting of short exercise bouts (three to five minutes) followed by rest periods.
While there is a link between physical activity and certain cancers, there still seems to be a gap in the knowledge of why physical activity seems to have a preventative effect on certain cancers. Some studies offer suggestions, but there is no clear reason of the “why” increased physical activity may help and “how” it may help.
There is not sufficient conclusive evidence to say that an increased physical activity level has a preventative measure against the development of all site cancers. However, as discussed above, there is strong evidence for the decreased risk of certain cancers.Practically speaking it is difficult to make general recommendations regarding frequency, intensity, and duration. No one individual or demographic will be the same. The key is to remember this and use gradual progressive exercise programming.
There has been a huge increase in interest in cycling over recent years as more people become aware of the health and fitness benefits’ cycling achieves, as well as its advantages as a fast and economical means of transport. Studio cycling has also grown and has been identified as one of the most popular group exercise formats in clubs worldwide.
Good bacteria can help you lose weight
For every probiotic evangelist there are several that sneered at the idea that these ‘good bacteria’ products did anything other than leave a big whole in your pocket. But according to a recent study, probiotics are very much more than a health food gimmick.
Probiotics, which are available as yoghurts, drinks and pills, contain so called ‘good’ bacteria that manufacturers claim aid digestive health and boost the immune system.
But the jury remained out – until now when a study has found that they do have many health benefits, including proving effective medicines and helping to control weight.
But you need to need to use the probiotics every day to see any benefits and you should be mindful of the sugar content (it’s best to opt for a pill over yoghurt) which will negate any of the benefits.
The definition of motivation is that which gives the impetus to behaviour by arousing, sustaining and directing it towards the successful attainment of goals. Abraham Maslow (1954) proposed that we all have a hierarchy of needs, the most basic being physiological needs such as food, and the highest needs being those related to self-fulfillment. Motivation directs behaviour – it organizes behaviour towards a particular goal state. It maintains behaviour until that goal is achieved.
The marathon is a long-distance running event with an official distance of 26 miles and 385 yards that is usually run as a road race. The marathon was one of the original modern Olympic events in 1896, though the distance did not become standardized until 1921. More than 500 marathons are contested throughout the world each year, with the vast majority of competitors being recreational athletes. Larger marathons can have tens of thousands of participants.
Although, all of the information that is presented in this article is geared toward the benefits and/or effectiveness of anaerobic high intensity interval training (HIIT) vs. low intensity aerobic training with regards to fat utilization, there is an understanding that some reasons for aerobic training supersede the outcomes. For the sake of pure enjoyment, personal goal setting (training for a triathlon, marathon, road race, etc), and the challenge of competition are all viable and respectable reasons for interacting with long slow distance (LSD) activities. For many people these types of activities are suitable for their lifestyle and enjoyable means of living an active life. The goal of this article is not to discount or diminish the value of physical activity in all its modalities, but to merely present data with regards to optimum fat loss, hormonal indicators, and other factors of cardiovascular and cardio respiratory markers as they pertain to exercise intensity prescription.
In the world of endurance, it seems that you cannot discuss fitness without discussing VO2 max. Ask any endurance athlete about it, and you will hear epic stories with names like Indurain, and LeMond. Many of you, however, may find yourselves wondering what exactly VO2 max is and why is it so important. To better understand this concept; let’s take a little trip back to school, specifically back to physiology class. According to the Essentials of Strength Training and Conditioning textbook, VO2 max is the maximum amount of oxygen in millilitres one can use in one minute per kilogram of body weight (ml/kg/min). In other words, maximal oxygen uptake (VO2 max) is the greatest amount of oxygen that can be used at the cellular level for the entire body. VO2 max has been found to correlate well with an individual’s degree of physical conditioning and has been accepted as an index of total body fitness. Numerous studies show that one can increase his/her VO2 max by working out at an intensity that raises the heart rate to between 65 and 85 percent of its maximum, for at least 20 minutes, three to five times per week. The estimated mean value of VO2 max for male athletes is about 3.5 liters/minute and for female athletes is about 2.7 liters/minute.
It is ironic that in this age of information, people continue to be confused about supplements. While in The UK alone, billions of pounds sterling are spent annually on vitamins, minerals, herbs, amino acids and other nutritional products, studies still show that people in all walks of life (including fitness professionals) need a good foundation in basic supplement information to help them make informed decisions about which products might best suit their individual needs. Because of this, the following is a list of what I feel are the top 10 supplements facts that can help save you time and money - and get the most out of the products you use.
Caffeine is one of the most heavily researched and beneficial ergogenic aids available. It is mostly consumed in coffee, with 1 cup containing around 75mg of caffeine. The understanding of the performance effect of caffeine has increased and this has widened its use. Most people know that “caffeine may improve performance” but what does it actually do and how can we make the most of caffeine?
Caffeine is classified as a stimulant and is the most common drug used in the world. Caffeine crosses the membranes of all the body's tissues. It can wield effects on the central nervous system and the peripheral tissues that result in physiological effects. Studies have shown that caffeine can help an athlete perform better. It has been shown to be a powerful ergogenic aid that is beneficial in athletic performance and training. Caffeine has been shown to increase speed and power output, improve the length an athlete can train, and assist the athlete in resisting fatigue. Caffeine has also been proven to stimulate the brain which contributes to an athlete's clearer thinking and ability to concentrate harder on the task at hand.
You’ve seen it before, and you’ll see it again. You have been intensely training for months, but you start to mention that you haven’t slept well for weeks, and the stress is starting to get in the way of your performance. You may suspect you’ve overtrained, which is quite common among competitive athletes. While overtraining can occur in a variety of different ways, it typically results from a combination of hormonal, neuroendocrine, and nutritional imbalances, secondary to heavy training (Kreher, 2012).
Hamstring injuries are prevalent in many sporting and training environments. They are the curse of many top athletes and urban warriors alike and have a horrible tendency to recur with monotonous regularity.
In the past, rehab specialists and trainers may have fallen prey to the hypothesis that "if it keeps tearing, it must be tight and therefore needs a stretch."
In this article I would like to pose a different hypothesis. One that looks at the length-tension relationships between the hamstrings at the back of the pelvis and quads and hip flexors at the front of the pelvis. We’ll look at how this relationship can contribute to these types of injuries.