Christina Applegate was diagnosed with breast cancer in 2008, at age 36. She had a double mastectomy and has been cancer-free since then.

One reason she has remained cancer-free may be her exercise routine, according to a Danish lab study published in eLife. The vegetarian actress and breast cancer activist does a combination of cardio, weight training, and a core workout for at least two hours a day, five days a week.

The researchers report that consistent physical activity boosts the ability of the immune system's cytotoxic T cells (specialized white blood cells) to knock out cancer cells.

It does that by increasing circulating levels of naturally occurring molecules and metabolites that are produced in muscle while you are working out. Those help activate cancer-fighting immune cells, which appear to slow tumor growth and may prevent recurrence of cancer.

If you are one of the estimated 1.8 million Americans diagnosed with cancer each year, you can do a great deal to make your fight against the disease more effective. With the advice of your doctors, beginning a daily workout routine is one important way.

Another self-help tool is adopting an anti-inflammatory diet free of red and processed meats as well as added sugars and syrups, and loaded with seven to nine servings of fruits and veggies daily.

It's estimated that up to 33% of cancer cases could be prevented with the adoption of such a healthful diet.

A meta-study in the journal Nutrients found that the Mediterranean diet appears to promote survival after cancer diagnosis.