Runners and Cancer

Original Editor - Kapil Narale

Top Contributors - Kapil Narale  

Introduction

It is known that running is one of the most common physical activities, not only for its physical and physiological benefits, but also for its versatility and ease of access. Running is also quite common in the cancer population, with notable benefits.

It is known that Physical activity is beneficial for the body, and helps to prevents many cancers, including colon, breast, and endometrial cancers. Infact, many studies have shown that physical activity and exercise is safe and permitted to pursue while an individual is managing their cancer. More information on this is explained on the Physical Activity and Cancer page. The activity can help support ongoing therapies, thus decreasing the risk of recurrence and death. In addition, many outdoor activities, including running, pose as a risk factor for skin cancer due to the exposure to strong ultraviolet rays, especially in the peak daylight hours.

Upon exploring (female) cancer patients, wanting to start or continue running, with normal controls, it is seen that there are many motivators in addition to barriers. Running with cancer is difficult, especially with managing symptoms and side effects, with uninformed trainers, and external factors such as receiving incorrect information.

This page begins to explore two sides to cancer and runners: how cancer affects patients who are already runners and how they manage to continue their activity of running, and what may be risk factors for healthy runners that may lead to cancer. The topics of personalised training and disease related factors for individuals who have cancer is considered, exploring how runner's exposure to the sun can lead to cancer, and the association between running and cancer in women, are explored.

Running with Cancer

Running provides cardiovascular, metabolic, musculoskeletal, and neuropsychiatric benefits, and is strongly correlated with a decreased body mass and smaller waist circumference. It is shown to increase one's lifespan, and is recommended as an exercise and means to prevent and minimise the effects of cancer, and other chronic diseases.

As mentioned, running with cancer is very difficult on the body, especially with managing any side-effects of the treatment and having uninformed trainers. Running programs geared towards oncological patients need to consider the patient's internal states and their effects while going through the particular cancer stages and it's treatment. The exercise treatment and training that is dseigned needs to be person centred, and consider the patient's limitations, designed by a qualified trainer, helping to motivate the patient and increase the patient's adherence, towards a healthy and active lifestyle.

Physical Activity and exercise, including running, can help with countering effects of the disease and treatment, such as fatigue, nausea, and vomiting, and improving the patient's quality of life. As for healthy individuals, it also helps these patients with cardiovascular fitness, strength, flexibility, and body composition. The American College of Sports Medicine outlines that cancer patients should not be inactive, and should participate in at least 90 minutes/week of moderate-intensity aerobic activity, and strength training twice a week.

There are factors that help motivate individuals to run, even after the cancer treatment. Some motivators for cancer survivors as well as healthy subjects included, prior exercise experiences, enjoyment, physical and mental benefits, exercise group support, family support, and the natural environment. Some motivators exclusively experienced by cancer survivors include, a cancer-related challenge, hope for other patients, support from friends, physician support, and organised training. On the other hand, barriers between cancer survivors and healthy subjects are quite different. Barriers for cancer survivors include, insufficient time in the long term, possibility of injury, side effects of the treatment or the disease itself, unqualified trainer, poor personal security, poor air quality, and the belief that exercise is only for athletes and body image.

Other factors that are beneficial to cancer patients include, becoming more knowledgeable about exercise benefits in cancer, and having the opportunity to train with other cancer survivors. This would help lead to adherence and compliance to their specified running program , and helping the runners to feel more informed, united, and conquer their mission together.

Exposure to the Sun

Exposure to the UV rays from the sun is a potent risk factor towards skin cancer. The knowledge, behavior, and attitudes of such athletes towards protection from the sun seems to be quite limited or not present. It is commonly known that individuals who participate in outdoor sports such as running do not sufficiently protect themselves from the sun, which can be a factor leading to skin cancer.

It is said that UV exposure may be facilitated by a change in the sunlight's absorption spectrum to shorter wavelengths due to the hydration of the stratum corneum, thus decreasing reflection and diffusion. This results in a greater UVB transmission, and a greater sensitivity of moistened skin to ultraviolet rays. UV exposure can result in a dose- and time- dependent facilitation of damage to one's DNA. This effect can be accelerated with sweating, as discussed below.

A greater risk of developing skin cancer is correlated with sweating, which increases the photosensitivity of the sun-exposed skin. This induces skin photosensitivity and activity-induced immunosuppression. There is no material in sweat that is said to increase the sensitivity of the skin to sunlight. The sweating caused by an increased exposure to the sun, heat, and physical effort while running outdoors can cause an erythema reaction, which can lead to an increased chance of a sunburn.

UV radiation is a primary risk factor of malignant melanoma (MM), and non-melanoma skin cancers (NM-SCs). Melanoma and non-melanoma skin cancers seem to be common in marathon runners. Melanocytic nevi and actinic lentigines are common within marathon runners, which are related to the development of malignant melanoma. The incidence of these skin cancers is gradually increasing worldwide, and is the most common in Australia and New Zealand. However, these are the most preventable types of cancers. Two-thirds of melanomas and 90% of other skin cancers are correlated with the overexposure of UV rays. Melanoma is associated with intense and frequent exposure to the sun, which can lead to sunburn. A study showed that lifelong exposure to the sun with outdoor running can be a risk factor for melanoma, which also relates to the duration of exposure.

Squamous Cell Carcinoma (SCC) can also occur in marathon runners. This can be associated with prolonged exposure to the sun, and a high cumulative exposure.

Individuals with a lighter skin tone can be at an increased risk as well.

Protecting one's self from the sun's rays can help prevent skin damage and skin cancers. Exposure to the sun's rays causes both chronic skin damage and sunburn. Sunburn occurs with extreme exposure to the intense sun, which leads to an acute inflammatory response. The radiation from the sun causes suppression of the immune system, which can lead to the development of cancer. Runners who may be overtraining can result with tissue injury, which may lead to immunosuppression.

Prevention and Protection

It is important that runners are aware of methods to protect themselves from the frequent overexposure t0 UV radiation, and with increased sweating. The level of sweating and environmental factors should be taken into account. This can help reduce skin damage in terms of sunburn, erythema, pigmentary disorders, photoaging, precancerous lesions, and skin cancers. There are many ways to protect from the intense sun rays.

Photoprotective agents can include:

• Natural agents, such as ozone, clouds, fog, pollutants, and the skin
• Physical agents, such as clothes (including sun protective clothing with UV protection factors (UPFs)), hats, or sunglasses
• Sunscreens, and
• Antioxidants, which are present in the diet, and reduce the oxidative effects from the exposure to ultraviolet radiation - this would include vitamin E (tocopherol), vitamin C, beta-carotene, and flavonoids.

Methods of photoprotection, and preventing skin cancer, can include: finding shade, minimising sun exposure in the peak sunlight hours, using sun-protective clothes, using sunscreen with an SPF of <30, covering your arms and legs with sleeves, and using hats and/or sunglasses. Sunscreens that are water resistant should be reapplied after 3 hours of perspiration.

In a study, it was seen that the most common protection from the sun used by runners was by wearing sunglasses. In terms of sunscreen application, 49% claimed they forgot to use it, and 17.3% found it uncomfortable. It is interesting to note that sun protection was more commonly used in runners who are women, elderly, completed fewer miles per week, with a lower BMI, and previously experienced skin cancer. In addition, it is seen that runners less than 45 years of age are more likely to experience sunburn. In a study, it was found that younger age, low Fitzpatrick skin type (I and II), or running for more than 3 hours a day, were risk factors for sunburn. In this study, the most common protective measures from UV radiation (from most to least common) were: sunglasses, sunscreen, wearing a hat, and protective clothing. A study by Christoph et al. mentions that older (between the ages of 35 and 54), fair-skinned (type I and II), and female runners have a greater awareness of skin cancer, and are more conscious of utilising protective measures. As well, individuals with a personal history of skin cancer had a higher photoprotection score, However, this was not the case in individuals with a family history of skin cancer.

In a cross-sectional online survey, seven sun protective behaviors were compared to note the differences. These seven behaviors, included the use of, sunscreen on the face and/or body, a hat, sunglasses, long sleeves, running in the shade, and avoiding running in the midafternoon sunshine. About 54%-84% of runners claim that they occasionally use some of these methods, but only 7-45% claimed that they frequently use these methods of protection. From individuals who did not use sunscreen, 49% claimed they forgot, 17.3% found it uncomfortable, and 6.1% wanted to maintain a tan, while 5.1% wanted to take advantage of the vitamin D intake. Other reasons people did not use sunscreen were they didn't believe they were at a higher risk of skin cancer, being ignorant of sunburn or wrinkles, and the expense of the sunscreen. When noting sun exposure behavior, 39.2% had a fear of skin cancer, 28.7% were uncomfortable, and 15.8% wanted to avoid aging of the skin. These behavior statistics were similarly found in the United States, and Europe. Within the study, it was found that the runners were most likely to wear sunglasses for protective clothing, and least likely to use full sleeve clothes. It was also found that facial protection, such as sunscreen on the face, hat, or sunglasses, were more likely to be used than full body protection, such as sunscreen on the entire body, or wearing full sleeves.

Breast Cancer in Women

It is known that physical activity can help reduce the risk of breast cancer. The association between running and risk of breast cancer may vary among women. It is seen that in younger, healthy and toned women, there may be greater risk of breast cancer in those with larger breasts. It is seen in previous studies that there may be a relationship of breast cancer with breast volume.

Women who run (or walk for exercise) are seen to be healthier and toned in comparison to other women. This may affect whether their breast size is a risk factor for mortality. When assessed at different exercise intensity levels, women who ran at a vigorous intensity (≥ 7.5 MET hours/week) were 41% less likely than those who ran at a moderate or light pace (< 7.5 MET hours/week) to be at risk of breast cancer.

In addition, higher circulating levels of estrogen are related to an increased risk of breast cancer. Physical activity helps to lower circulating estrogen, thus lowering the risk of breast cancer. Women with larger breasts and a narrow waist, seen in physically active women, have a much higher estrogen concentration, as opposed to women with a larger waist.