The Importance of Physical Activity for Seniors

Broadcast from KSQD, Santa Cruz on 7-10-2025:

• Dr. Dawn responds to an email about lion's mane mushroom blood thinning properties. Lion's mane contains hericenones that inhibit platelet aggregation but promote nerve cell growth. People on blood thinners like Eliquis or those with bleeding disorders should stop these supplements before surgery. She recommends lion's mane for cognitive preservation effects despite bleeding risks, emphasizing the need to balance benefits versus risks.
• An emailer asks about Fatty15 (C15:0 pentadecanoic acid) supplements marketed for longevity. Dr. Dawn finds promising research, however, most studies are in animals with limited human data. She warns against over-supplementation and recommends food-first approaches, suggesting cheaper alternatives like berberine may provide similar benefits.
• A visiting guest asks about continuing L-arginine after blood pressure normalized. Dr. Dawn recommends continuing L-arginine as it helps produce nitric oxide and prevents age-related arterial stiffening. She explains how blood vessel elasticity decreases with age, creating feed-forward cycles leading to permanent hypertension. The guest also asks about iodine safety - Dr. Dawn confirms 1mg daily is safe, noting Japanese populations consume up to 4mg daily without problems.
• Another visiting guest inquires about memory-boosting supplements (nootropics). Dr. Dawn identifies nicotine and caffeine as effective options, mentioning she uses nicotine patches for test-taking focus. She discusses lion's mane as effective for cognitive enhancement and coffee blends combining both ingredients.
• A caller asks about tirzepatide (Mounjaro) for weight loss at age 73, concerned about muscle loss. Dr. Dawn emphasizes the importance of branched-chain amino acids and 20-30 grams of protein before exercise for older adults to build muscle protein. She explains younger people can build muscle while fasting, but older adults need circulating protein during exercise to activate muscle-building DNA. She recommends alternating upper and lower body workouts and checking testosterone levels.
• Another caller asks about rapid resting pulse rate (80-100 bpm) at age 74. Dr. Dawn suggests checking blood pressure, as low blood pressure can cause compensatory heart rate increases. She explains age-related changes in blood vessel reflexes that can cause blood pooling in legs and orthostatic changes. The caller also complains about pharmaceutical advertising, prompting Dr. Dawn to criticize direct-to-consumer drug marketing for creating artificial needs through emotional manipulation.
• Dr. Dawn warns against P-Tau217 blood testing for Alzheimer's screening, calling it inadequate for general population screening. The test has poor predictive value below level 10, creating many false positives in low-risk populations. She criticizes associated drugs like donanemab (Kisunla) for severe side effects including brain swelling and hemorrhage. Instead, she recommends lifestyle interventions: exercise, stress control, adequate sleep, reduced alcohol and sugar intake for memory concerns.
• She criticizes FDA approval of a new blood test for colon cancer screening with 83% sensitivity for detecting existing cancers but poor sensitivity for precancerous polyps. Dr. Dawn criticizes this as inadequate screening since it detects cancer after "the horse has left the barn" rather than preventing it.
• In closing remarks with her impromptu guests, Dr. Dawn addresses a question about intermittent fasting and exercise timing. She explains that exercising while fasting provides cardiovascular benefits but won't build muscle mass in older adults. She recommends bioimpedance analysis testing to track lean body mass annually in seniors and emphasizes the importance of progressive resistance training to prevent age-related muscle loss.