Science AMA Series: I’m Karen Mustian, Ph.D., M.P.H., associate professor at the University of Rochester Medical Center, and I’m here with Ian Kleckner, Ph.D., research assistant professor at UR and its Wilmot Cancer Institute. We study exercise in connection with cancer. AMA!


Hi Reddit!

I’m Karen Mustian, an associate professor at the University of Rochester Medical Center. I’ve been studying exercise for cancer patients for 12 years, and several of my team’s studies have been highlighted by the American Society of Clinical Oncology (ASCO). People with cancer often become extremely fatigued either because of the disease or the treatment, and they also might suffer from pain, nausea, and other problems such as “chemo-brain.” Our research shows that exercise helps with many of these symptoms.

In past years, most cancer patients were told to stay home and rest. Now, exercise physiologists like myself with a special interest in cancer, are trying to learn more about and define “exercise prescriptions” for many patients. Cancer and its treatments can impact the heart, lungs, muscles, bones, and immune system. Therefore it’s important that we carefully develop safe and effective exercise programs with realistic and achievable goals. I’ve been investigating the benefits of gentle yoga, walking, and strength training with resistance bands.

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I would imagine that the biggest issue for cancer patients (re: exercise) is finding the initial strength and fortitude to begin a workout. If I feel sick, it's hard to start exercising even though it always almost instantly helps me feel better.

What do you recommend as a way to get patients up and moving in the first place, when they feel really sick and tired? What are your opinions on the efficacy of doctor-monitored exercise apps, that let the docs monitor their patient's routines in order to hold them accountable to a regular regimen? (Ex, doc says "hey Danny, I saw that you missed your workout yesterday. Let's talk about why you missed, and how we can get you moving today").


The answer to the first part of your question is that you're absolutely right: this is usually one of the biggest barriers for cancer patients. The first thing I would suggest is to take it very very slow and easy. Start by just simply trying to walk a little more every day. So, for example, people hear the word "exercise" and think it needs to be more difficult and vigorous than it actually needs to be.

Moving your body in any way is helpful to get moving in the first place-just start with anything you like and that feels good.

There is no evidence that doctor monitored apps are any better than any other apps or ways to exercise that help to motivate you. Pick what you like and use that.

My grandfather was diagnosed a few year back and he's still fighting but with limited mobility. He has no idea what's wrong with him, he refuses to listen to the doctors and only my grandma sticks around for the serious talk. Because of this, he's in complete believe he can go out and do whatever he wants, against what the doctors are advising him. He's held out much longer than anyone thought and I believe it's largely got something to do with his exercise and mindset. I think you're onto something. Thank you for spending your time to look at these.

My question is, what's been the biggest surprise so far in your research? What was the moment you realised there was a genuine pattern?

EDIT: For clarity, we're from the UK and his doctors within the NHS have been good so far. His cancer is aggressive and has spread to his spine, legs and brain. He doesn't know any of this, he refuses to hear any of it. He's still planning next years fishing trip.


This is a great story! Kudos to your grandfather. My greatest discovery/surprise in my work was the day I saw in my work that winning the war against cancer was a personal battle and that it was not as much about how long you survive but more about how you survive. Living your life with quality-moving is the key to this for many people and movement becomes a way to heal and life to fullest on their terms regardless of the actual disease state.

I suppose that we should start easy here:

What are the connections between exercise and (reducing the incidence of) cancer?

Does exercise inhibit cancer(s) and if so how? Which ones?

Are there any specific types of cancer more so affected by exercise than any other?

What does the long term data say about cancer and those who have exercised all their life? (Yeah...this one is self-serving but I've been exercising since I was very I'd like to have an idea if it helps at all or if I should just quit and start drinking more beer now.)


Thank you for your question, unfortunately, I do not study exercise for the primary prevention of cancer. I study how to use exercise with patients after they have a diagnosis. So I am not able to answer your questions here. I can say that exercise helps in many ways-increasing your fitness is crucial for the day that you face any illness as it will help you to face it with more functional capacity reserves-it is just like saving for retirement. Keep exercising-but it is okay to have that beer sometimes too!

Can you explain how with ever changing chemotherapy regimens does continuous exercise impact overall outcomes when chemo regimens are hit or miss for 100% of patients for their bodies to respond to?


Based on the existing research, which is predominantly among patients with breast cancer (there are a few studies in patients with other cancers), it does not matter what the chemotherapy regimen is. Patients are in fact able to do low to moderate intensity exercise and they have favorable outcomes demonstrating fewer toxicities and side effects.

Hi Dr Karen and Dr Ian What sort of effects both positive and negative have you seen regarding the mental health of patients in response to the exercise? What is the biggest inhibiting factor you face when increasing levels of exercise in a patient?


The biggest barrier to increasing physical activity is just getting people started. This is because they often think they have to start by doing far more physical activity than they need to. For example, you don't have to run a mile, take a yoga class, ride a bike for 30 min. You can simply start by walking for 10 min and slowly but surely increase that over time.

I haven't seen exercise result in negative mental health outcomes. The closest thing I can think of is when someone is really super active/fit and mentally it is really difficult for them to initially cut back on the amount of physical activity they do and move forward slowly. Across the board, I have seen significant improvements in worry, anxiety, depression, cognition, stress, distress, and many other mental health outcomes with as little as 10-15 min/day of physical activity.

I don't know if you can, but could you explain the parameters of your research study? As in how are you going about with this study? Especially since the ramifications of potential findings could potentially be very long term.

Do you know the specific cancer mechanisms that are affected by exercise and how?

How did you get into this field and choose this particular area of study?

Thank you for this AMA!


I have many research studies. Do you have one in particular you are interested in knowing more about?
In general, I recruit patients just prior to treatment (e.g., chemotherapy and radiation) and prescribe different exercise interventions (e.g., walking, weigh lifting, tai chi, yoga) and I do a series of measurements based on the outcomes we are interested in for that study (e.g., fatigue, depression, insomnia, infections, immune dysregulation, cardiovascular function, etc). We randomize the participants to two group (one gets the intervention and one gets a control condition) and we follow them over time. If you would like to see some more info on study designs you can look up my work on and see all this information for several studies.

This sounds like a great move in the right direction to improving the lives of those affected with cancer. After everything these patients have been through, how would you account for the lack of motivation and will power that would get these patients through their prescribed workout?

Since different cancers come along with different challenges, what types of cancer are you looking at specifically and why?


In my experience, patients do not have a lack of motivation and will power, once they are given the proper information about what it is they really need to do. Most people may feel disheartened because they they think they need to do far more than is really needed to get started. Prescribing a realistic exercise prescription and not over doing it is of real importance. Also, the prescription needs to be specific to the outcome they are interested in influencing relevant to their cancer (e.g., they want to reduce fatigue or neuropathy) - these are often not the same as the general fitness outcomes people without cancer have (e.g., look good, lose weight).

Can you identify the mechanisms of action that exercise benefits cancer patients? Are they the same mechanisms that apply to the general population? For example, reduced blood pressure, increased HDL, reduced inflammation.

Also, my understanding is that due to genetics a certain small percentage of the general population are 'non-responders' to physical exercise, and don't experience a positive response to training, are different regiments recommended for these people versus the 'responder' population?


We don't have a clear body of knowledge to know for sure. Some hypothesized mechanisms include increased physical conditioning responses that positively influence functional outcomes like cardiovascular function, muscular function, neurological function, etc. Some others include regulation of immune function-specifically regulating inflammatory processes. With respect to genetic influences we are just beginning to really learn how exercise influences the epigenetic landscape in people without cancer. I have recently been able to show that exercise created a positive influence on the expression of a set of genes in prostate cancer patients-we are now pursuing work to look at the effects of exercise on transcription and translation and the influence of single nucleotide poymorphisms (SNPs) in cancer patients. It is too soon to say anything for sure yet but these are exciting new areas we are studying.

Thanks for your question, but it is hard to fully answer your question in a forum like this because the answer is very complex.

Did you begin the research with any ideas that you now believe to be false?


Basically, when I started doing this, I thought I needed to prescribe the same dose of exercise for cancer patients that we recommend to healthy individuals (e.g., CDC exercise guidelines), and that the only outcomes that were important were changes in physical fitness. I now know that the exercise prescriptions that are effective for cancer patients are all over the map and can be far less than the CDC-recommended guidelines.

The outcomes that are important to cancer patients are much more expansive than just physical fitness; they include goals like treating fatigue, peripheral neuropathy, cognition, infections, inflammation, depression, worry, anxiety, insomnia, and the list goes on.

My understanding is that chemotherapy affects everyone differently and to varying degrees. How do you control for the incredible number of variables involved in research like yours? How to you prove causality vs. correlation? Is it simply a question of sample size?


These are great questions. I only conduct large, Phase III, randomized clinical trials, which is the one and only study design that allows you to infer anything about cause-and-effect. Part of the beauty of this study design and why it is considered a gold standard is because it allows you to control for many variables through the process of randomly assigning patients to study conditions (e.g., exercise vs. control) and other design characteristics. Sample size is part of this but it is not all.

Hi Dr Mustian and Dr Kleckner, thank you very much for doing this AMA. For me, it's like a godsend because a close family member was just diagnosed with metastases, and I have a burning question concerning workouts with cancer:

  1. What kinds of training do you suggest for cancer patients specifically in preparation for and also during chemo?

  2. How would a patient know that he works out too much?

A friend's father was diagnosed with cancer. He then followed a strict workout regimen that wasn't too hard but he trained every day, mainly doing sit ups, also during chemo. His tumour shrank more than expected and the doctors said there was quite probably a causal link between him working out and the tumour decreasing.

  1. Does this mean that a patient who was now diagnosed with stage 4 breast cancer (metastates in the lungs, 12 years after having successfully overcome the primary cancer) could and should follow this kind of training?

  2. How would she know when to pause from training and when to push through?

  3. What kinds of training do you suggest?


Wow I'm incredibly happy that you found us today! I'm going to offer some overall suggestions: first, it's important for your family member to talk with their oncology team about the fact that they would like to be physically active, and to have an open conversation about how best to do this.

Second, you can help your family member by looking through your community to find qualified exercise professionals who have experience with cancer patients. Some things to look for are people who have a Bachelor's degree or higher in exercise science or kinesiology or physical therapy along with certifications from the American College of Sports Medicine. These degrees are just a starting place, you also want to talk to them and find out what their experience is. It's important to make sure that whatever type of exercise professional that you work with understands the unique complications that cancer patients experience, what their needs are, and how exercise needs to be prescribed differently in order to be safe and effective. These individuals (your oncology team and your exercise professional) should communicate and work together to help you get your questions answered and to help your family member.

We also have shown in some of our research that it can really be beneficial for care partners to be physically active with their loved one who has cancer. The common activity can help provide support for both individuals and can lead to lower distress as they navigate the cancer experience.

I've been running for many years (daily 3 miles and half marathons) prior to being treated for cancer. For me, any exercise during chemo/radiation helped immensely. I have been cancer-free for a year and am still running although not as long or fast. The surgery and radiation I received in my groin I believe has helped slow me down (scar tissue). What side effects can athletes experience after chemo/radiation? What can be done to ease side effects? Also I would love to contribute to your research if you need it.


Athletes experience the same exact side effects as non-athletes during and after their treatments. Keep exercising to reduce your side effects it helps, but make sure to not over do it as that is frequently the biggest problem athletes have when they have cancer and continue to exercise; they can often exacerbate side effects because they exercise too much or too intensely unlike their non-athlete counterparts.

I love this idea! Thank you for taking time to answer our questions. Exercise obviously affects the way the endocrine system works, and the endocrine system affects so many other systems in our body. Have you seen any evidence in your research suggesting that one particular system, aside from the immune/lymphatic system, plays a major role in cancer treatment and recovery?


This is Dr. Kleckner: this is a great question, thanks. A few thoughts: first, the brain is an important mediating system of the effects of cancer/treatment on health-related outcomes (fatigue, neuropathy, cognition, etc.) and the effects of exercise on health-related outcomes. We know that exercise influences the brain in multiple ways from studies in healthy people. Here, we are beginning to look at this in patients with cancer as it relates to neuropathy and cognition.

Second, as I transitioned from interested-lay-person to researcher, I found it fascinating to realize the active role of bodily tissues such as fat and muscle in their effects on physiological functions (e.g., contracting muscle releases cytokines that influence the immune system in beneficial ways).

So, I assume the obvious that more regular exercise may mitigate the chances of cancer... But is there a limit to how much cardio or lifting etc you should do to not expose yourself somehow to greater risk of cancer? Might sound ridiculous but science baffles me every day, so figured I would ask.

Also, do you study exercise supplements and how they may affect chances of cancer?


Thanks for the interesting question. I am sorry but I do not study supplements. I also do not study exercise as a tool for primary cancer prevention.

Is your research completely about the benefits of exercise post-treatment, or have you done/know of other studies looking at levels of exercise before diagnosis/treatment?

Have you found any particular types of exercise to be more effective than others?


I do work with patients during treatment and after treatment. There is no particular mode of exercise that has been shown to be more or less effective. If you are thinking of becoming more active, it is more about how the particular mode of activity is prescribed (i.e., number of times per week, length of session, intensity level, etc.). The most important thing is to pick some type of movement that you like to do and enjoy. The field of exercise oncology has not evolved to the point of being able to tell us if there is a particular type of exercise that is better than another type of exercise for specific cancer-related outcomes.

I'm an exercise physiologist who works a lot with post rehab clients, many of which are also cancer survivors. As someone who has had an exponential amount of experience in cancer related research, do you believe any exercise modalities to be detrimental to long term recovery?


Research has not shown that any particular modes of exercise are particularly detrimental, but it could be possible to prescribe a particular mode of exercise in a manner that is harmful.

What does it take to become a researcher on your team? I graduated with a degree in exercise science and would love to help out in this type of research.



I'm so happy to hear that you are interested to contribute to our field. If you want to become an active scientist, you will need your PhD in an exercise-related field. After you finish your PhD, apply for cancer-related positions (likely a post-doc). These are very competitive positions so be prepared to apply for several jobs all over the country.

It is difficult to exercise when feeling tired and weak. Do you ever prescribe/recommend caffeine or other stimulants in conjunction with exercise?



Hi, My father was diagnosed back in may with stage 3 cancer in the esophagus. He recently finished his radiotherapy and chemo. During the treatment he was relatively fine, he would still go out for his morning jog. Now he barely moves around the house (he's not postrated). I've seen how he gets dizzy and sleepy after he eats.

My question. What kind of excersises are good for him to recover his mood and get better before the surgery.

edit: he used to lift weights and play hoops


One of the modes of exercise that has the biggest effects on mood in my studies is yoga. Although some men may not feel that yoga is a good fit for them, yoga includes strengthening your muscles, which is something men are often interested in. My work with gentle hatha and restorative yoga postures combined with the meditation aspects, which include simple breathing and attentional focus activities, have been highly successful at improving mood, anxiety, fatigue, and quality of life.

Do patients develop issues like CRPS that make it more difficult to create exercise regimens?


We assume that by CRPS, you mean complex regional pain syndrome. We see a lot of complex issues in patients, not just those related to pain. And yes it can make it more challenging (but not impossible) to prescribe effective exercise regimens.

What considerations do you take with regard to the spread of cancer within the body? If I recall correctly it has been suggested that cancer may spread via blood circulation, how likely would it be that any issues arise from physical activity with the affected area and/or an increased heart rate (thus blood flow)?


Unfortunately this is not a widely studied area, so we don't have an answer.

Have you been able to observe the effects of exercise with chemotherapy, compared to exercise with holistic medicine?



Thanks for taking the time to do this AMA. For the last three years I have been exercising constantly. I had been in poor condition 3 years ago and decided to turn my life around. I had quit smoking 10 years ago. I quit drinking at the same time I started exercising. I began with boot camp exercises 3 years ago and one year ago began cross fit three times a week with bicycling. I bragged to my wife I was the poster boy for fit 60 year old men. Then I was diagnosed with acute lymphoblastic leukemia one month ago. I was immediately admitted to the hospital and within 2 hours underwent leukopheresis (430,000 cancer cells per microliter). This was followed by strong chemo therapy withing 12 hours. I was hospitalized until yesterday and am now at home. During hospitalization I exercised a little. Walked and lifted some light weights. Now that I'm home what exercise routine would you recommend? I have 20 lb kettle bell, 5 and 10 lb dumb bells, bands and walking shoes. I am starting second round of chemo and really don't want to waste away.


I am so sorry to hear about your diagnosis. I think it is great you want to keep moving. I would recommend that you start very easy and slowly with your exercise. No need for Crossfit here. Start by walking and with the lowest weights you have and just a few repetitions with one set. I would also recommend you talk with your treating oncologist about how to resume your activity and that you find a local exercise professional who is trained to work with cancer patients. This would mean someone who has a degree in exercise physiology, exercise science, kinesiology or physical therapy and who has experience working with cancer patients. Good luck! Start low and progress very very very very slowly.

I have a 19 year old son with some type of polycythemia but supposedly without the gene for it (which is an entirely different and difficult lab issue).

Anyway, he makes too many red blood cells. His spleen enlarges and he has to have phlebotomies every 4 weeks. After 2-3 weeks, he usually cannot eat very much much at a time again, as his spleen swells to the point of compressing his stomach.

In this case, where, as I understand it, his red blood cells are not delivering oxygen to his cells, therefore they are sending a message to his brain that they don't have enough oxygen, so thehis marrow makes more RBC's, etc; would exercise like light cardio be of any effect in delivering oxygen?

in other words, if the defect that's causing the condition is related to not being able to release oxygen, would cardio have any benefit or would that just be kind of cruel to his body and soul, forcing him to do cardio, if the oxygen wont release no matter what he does?

He has hemochromatosis as well, and a crappy oncologist, whom I hope to leave tomorrow and head either to a major cancer center or genetics, based on the best decision I can make.

But today's question for you is specific to his RBC issue: is there any point in cardio if the problem is his RBC's won't deliver oxygen, no matter what he does?

I'd really appreciate any thoughts you have. I know this is specific and not general but it haunts me at all times, trying to find ways to help him not spend all his marrow and convert to acute leukemia. He is only 19. This is a disease that rarely ever affects someone so young, and it is heartbreaking to handle.

Thank you in advance,


I am really sorry to hear this. Your situation is very complex and it is hard for me to give you an answer over the internet. While exercise can provide a conditioning effect that helps us to deliver and utilize oxygen better, it also can cause a person to exert to the point of creating an oxygen debt. I cannot give you a specific answer but I would encourage you to talk with your son's hematologist about this. I wish you the best and your son.

Hi! Have you discovered any particular factors (without giving away unpublished data) that seem to significantly impact the affect of exercise in symptom coping, examples of said factors could be age, gender, type of cancer etc.


No there is no particular factor I have discovered as of yet in my work.

Sorry for the simplistic question, but do you think there will ever be a cure for cancer?


That is not a question I can really answer.

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