I Sleep and I Sleep, yet I’m Still Exhausted – Cancer + Fatigue


If you finished treatment months ago and are still feeling exhausted, no matter how much you sleep or rest, you’re not alone.

Fatigue is one of the most common complaints people have after cancer treatment ends, often because it doesn’t seem to go away. This is a very different experience than being overworked or not getting enough sleep. Cancer-related fatigue can be caused by your body’s inflammatory response, the increased metabolic demand of cancer, and even blood changes that can occur as a result of chemotherapy. This is why you can sleep more, rest more, and still wake up everyday feeling just as tired as you did the day before. It’s a frustrating cycle and for so many, it continues much longer than expected.

Why Cancer Causes Fatigue

There are two reasons why cancer can cause fatigue all on its own:

1. Increased Inflammation

There’s still so much we don’t fully understand about cancer but research shows that cancer comes with a lot of inflammation. Cancer cells grow much faster than our healthy cells, and our immune system responds to this unusual
growth, in part with inflammation (with the goal of killing and removing them from our body). As with most things in our body, inflammation can be a good thing, until it’s out of control. As the speed of cancer cell growth increases, our immune system cannot keep up, but it tries! This is when we start to see chronic inflammation, which can actually cause or worsen your experience of pain and fatigue.

2. Increased Energy Demand

The presence of cancer can increase your body’s need for energy, weaken your muscles, damage certain organs (such as liver, kidney, heart or lungs), and/or alter your body’s hormones, all of which may contribute to fatigue.

Why Cancer Treatment Causes Fatigue

Radiation and chemotherapy are often mentioned in the same breath, but let’s be real, they are completely different treatments and often cause unique challenges. When we’re talking about how tired you’re feeling, both can hit you pretty hard, but the how and why looks a little different.


This targets the exact location of your tumour and you may find that for the first few days or weeks of treatment you are able to go about your life as normal (except for this new full-time job of appointments and treatments). Radiation causes cells to break apart and die (which is why it’s so effective against cancer) but the by-product of this cell damage is inflammation. Your immune system then tries to clear out debris and heal the tissue damage. The compounding effect of daily treatments ultimately catches up with your body and can lead to lingering fatigue that stays with you, long after treatment is over.


This is a much more systemic (or whole body) treatment and those drugs are powerful. Fatigue can occur as your body tries to repair the damage to healthy cells and tissue, or as a direct side-effect of treatment. You may develop anemia if treatment destroys too many healthy red blood cells, or experience hormonal changes. For example, changes to your thyroid gland, adrenal glands, or ovaries can all alter your hormone levels and cause or worsen fatigue.

Great, It’s Complicated. So What Can I Do About It?

What I hope you find here is encouragement and hope, knowing that with a little more knowledge you can take steps to support yourself. What we eat, how we move, and what we do to reduce both physiological stress and mental-emotional stress all helps to reduce inflammation and support recovery from this frustrating cycle.

Here are the most foundational ways you can start to treat cancer-related fatigue:

Increase Your Movement

No doubt you’re a little irritated as you sit there reading about fatigue, only to have me recommend physical activity. However the research continues to show that exercise significantly improves both chemotherapy and radiation-related fatigue. Avoid high-intensity activity as this will spike your cortisol and push your body too hard. Instead, choose something you enjoy, that’s easy to access regularly – walking, yoga, swimming, etc. As little as 15 minutes/day can be enough for you to start seeing the benefits.

Add Anti-inflammatory Foods

The fatigue-reduction diet has been studied in women who completed breast cancer treatment and it was found that both sleep and fatigue improved significantly. The fundamentals of this are:

  • a. Ensuring at least ½ of your grain intake is from whole grains
  • b. Including 5 servings of vegetables daily (at least 1 leafy green, 1 yellow or orange
  • vegetable, and 1 red vegetable)
  • c. Adding in 2 servings of fruit (1 of which should be high in vitamin C)
  • d. Including 1 serving of fish daily
  • e. Adding in 1 serving of omega-3 fatty acid-rich nuts or oils
Consider Botanicals

Panax Ginseng is an adaptogenic herb that has been shown to be both safe in patients with cancer-related fatigue and beneficial for improving fatigue, appetite, and sleep. Ginseng can be fairly stimulating (which is why people love it), so avoid taking it in the evenings or before bed.

Remember that “natural” doesn’t mean safe, and every person is unique. What your neighbour experienced and how they supported themselves may or may not be the right thing for you, and that’s ok. You’re on our own timeline and need support that’s right for you. So don’t be afraid to ask questions and listen to your body.

– Yours in health, Dr. Hayhlee Clarence, ND


Dr. Hayhlee Clarence is a Naturopathic Doctor and co-owner of The Orenda Clinic & Apothecary in Toronto, an integrative clinic created to support digestive and hormonal health, including reproductive cancers. Her practice is focused on cancer support both during active treatment and long-term, as women recover and look to take care of every aspect of their health.

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