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Drinking water, creatine

Created date

June 25th, 2013

Q. I am a fairly active 80-year-old man. Do I still have to drink eight 8-oz. glasses of water every day?

A. Water is certainly important for all bodily functions and even mild dehydration can be harmful for some people. But the 8 x 8 water rule is simply a general guideline for healthy adults and is not well supported by scientific evidence. The Institute of Medicine recommends that healthy males need about 3 liters (or about 13 cups) of total fluids per day (2.2 liters or 9 cups for women). Factors that affect your fluid needs are exercise, your environment, medications, or the presence of illness and chronic conditions. Your daily total fluids can come from water, milk, juice, and other beverages. Drinks containing caffeine and alcohol should not be counted toward your daily intake, however. Talk to your doctor about your specific fluid needs.

Q. At 90 years of age, I have decided to work on preserving my muscle strength. I have heard that creatine can help, but is it harmful to take at my age?

A. Creatine occurs naturally in the body, and has a role in making the energy needed for muscles to function properly. It is also available as a dietary supplement. So far, there is some scientific evidence that creatine may improve athletic performance in young, healthy people, but studies show that it doesn t seem to improve strength or enhance muscle building in people over age 60. Although creatine is likely safe when it is used in recommended amounts, it can have side effects such as abdominal pain, nausea, vomiting, and muscle cramps. In higher doses, however, it might be harmful to the liver, kidneys, or heart. It is not known how creatine interacts with medications. If you want to build your muscle strength, talk to your doctor about how to proceed. Resistance exercises have been shown to be beneficial for older adults. Send questions by email to

Eugenio Machado, M.D.  

Senior Medical Director


Silver Spring, Md.

Dr. Machado earned his bachelor s degree in chemical engineering from the University of Maryland in College Park. He received his medical degree from the University of Maryland Medical School and completed his internship and residency at Maryland General Hospital in Baltimore. Machado is board certified in internal medicine. He joined Riderwood in February 2004.