Cholesterol Fluctuation
There seems to be an assumption in lipid testing that serum levels remain relatively consistent over short periods of time. But there seems to be little evidence on this, and the evidence I've seen, including personal and other anecdotal evidence from more frequent testing (one or more times per week) as well as the only study I've found suggests that serum lipid levels can fluctuate materially by week and even by day. (Mogadam et al., Within-Person Fluctuations of Serum Cholesterol and Lipoproteins, Arch Intern Med. 1990;150(8):1645-1648.) Do you have any insight into such fluctuations, and might this suggest more frequent testing, both to better assess serum levels and to determine how they fluctuate bioindividually with diet and exercise?
PCSK9-Repatha and HbA1c
Hi Peter, I started taking 140 of Repatha about 18 months ago in addition to the Crestor (5mg) and Zetia (10mg) and its lowered by cholesterol from 187 to 95 but my HbA1c has increased from 5.4 to 5.8 while my fasting glucose has decreased from 118 to 100. Should I be concerned about this?
Insulin spike with whey protein isolate
I've come to understand that ingestion of whey protein isolate can stimulate an insulin spike, likely in response to the quickly metabolized amino acid load, especially methionine (and to some extent leucine), which is abundant in whey protein. In light of strong recommendations to closely manage our insulin-signalling system, I would be grateful for some insight both into the mechanism for this insulin response and whether this is something we should be concerned about, particularly since whey is such good option for protein supplementation. I am aware that such an insulin spike may be disconnected from a spike in blood glucose, which of course, we're always looking to minimize.
Athletic performance and Metformin
Hi Peter, Thank you for taking the time to share your vast knowledge on so many health related topics! I'm truly grateful and enjoyed your book. I am living proof! Benefitting from your podcasts and videos! My question is related to the 2019 study on exercise and Metformin. Aging Cell. 2019 Feb; 18(1): e12880. Metformin inhibits mitochondrial adaptations to aerobic exercise training in older adults. I was prescribed Metformin 500 mg this year for pre diabetes numbers from recent bloodwork. Although just in the last month I stopped Metformin due to extreme fatigue. I've cleaned up my diet trying to do everything I can to stave off Diabetes. I'm a 60 yr old 57 kg lean body mass lifelong cyclist, home in the Rockies; not too many zone 2 area rides where I live. My 2023 LT test results were very good. Then I began Metformin 500 mg and could not tolerate the same levels of exercise which include cycling, weight-training, swimming 2 days a week. My training is reasonable for my age and functional threshold numbers - A normal decline with my FTP as I've aged thru the years, but I've adjusted my training to those numbers. Within 2 weeks of taking Metformin the fatigue was unrelenting. I want to reap the benefits of Metformin but I'm very worried about the extreme fatigue, dizziness and spike in HR while training. // Should I just began the Metformin protocol again and try to train thru this? // Will my body adjust? OK well there's two questions. Thank you!