In Part 1 I introduced my study and talked about the preliminary research I did on caffeine and performance. Moving on then, let’s see what the literature says about cold water immersion as well intermittent fasting.
Research and Methods: Cold, Recovery, and Sleep
Cold showers used within one hour of a workout you will effectively make you feel better, but perform worse (i.e. muscles tighten and contract in the cold). However, it was found that cold showers in addition to active recovery within 24–48 hours decreased perceived soreness, but yielded no significant change in subsequent performance. This has merit though, because if you don’t feel good, it will be more difficult to stay motivated to do a given task. Some studies suggested that it may take up to 6–12 weeks for “full effect” to set in. In addition, RHR may stay lower, longer when cold is followed by exercise. Which, RHR can be used as a in indicator of recovery (which it is in my study) ( r, r, r).
Insomnia has been shown to increase blood sugar and blood pressure, both were monitored throughout my study ( r). Increased blood sugar can increase inflammation and otherwise slow recovery, which will be checked in the data analysis ( r). In contrast to blood sugar, magnesium, zinc, and selenium have been shown to aid recovery (reference above). “Interestingly, magnesium has been shown to exert, as IGF-1 does, beneficial independent actions on muscle function and could play a role on physical performance in the elderly. This hypothesis is consistent with clinical and epidemiologic data supporting the importance of the magnesium ion as a determinant of muscle performance in young subjects.” “There is increasing evidence that selenium could influence skeletal muscle function even if its role in maintaining functional muscle efficiency is still unclear.” (ref. above); Selenium is also related to production of thyroid hormone T3.” “Zinc is involved in growth, protein and DNA synthesis, neuro-sensory functions, cell-mediated immunity, thyroid function, and bone metabolism”… zinc seems also to be involved in nutritional regulation of IGF-1 bioactivity. In cultured bone cells, some studies suggest that zinc potentiates the action of IGF-1 and increases endogenous IGF-1 synthesis.”
Tim Ferris ( The Four Hour Body, p.258) suggested 2 x 10 min cold showers / day in addition to 10,000 IU of sunlight to boost testosterone. However, I found one article that stated that cold showers won’t do anything for testosterone that exercise won’t ( r). Cold showers may still effect IGF-1, though it’s contested whether it is the circulating volume or concentration that increase ( r, r). Vitamin D may increase testosterone ( r). You get 10,000–20,000 IU / 30 minutes in the sun ( r).
In my testing I timed the length of my cold showers and used all cold tap water. Shower times were randomized throughout the study. I also used an Athletic Wellness Questionnaire to measure recovery. RHR, as well as AWQ and Blood Pressure, were taken the morning after a given workout (e.g. workout on Tuesday, measurements Wednesday morning).
Initially I wasn’t particularly interested in IF, though it was frequently requested on my Instagram to look at next. My initial research found some benefits to IF ( r). As for insulin resistance and inflammation, see above regarding blood sugar and ketones. At my current training rate, certainly before the COVID-19 scare, and thereby gross recovery need, I wasn’t concerned with autophagy either. Nor am I convinced that IF would give a benefit greater than the protocols I’ve already mentioned. Though, I’m curious enough to monitor it throughout testing and include it in the statistical analysis since I did start a fasting protocol as part of the #carnivore75hard challenge. IF can also aid in weight loss, though I suspect this is largely due to portion control. I’m very happy with my current weight and body composition (160–165 lbs, < 10% body fat).
There are also potential drawbacks of which specifically have to do with strength gains related to IGF1 ( r). In short, I’m happy with my weight / composition and want to get stronger more than I want to get lighter / leaner. Additionally, IF has been shown to lower blood pressure in short term trials (< 12 weeks), but the confidence interval ( p) become “rather abysmal” after that ( r, r).
Commonly used fasting intervals range from 14–18 hours, or 5:2 (5 days eating normal, 2 days water fast or minimal calories) ( r). I did get more comfortable with fasting as time went on and actually tended to prefer longer fasts of 20ish hours. Initially I didn’t think I could get all my food for the day (2,500–3,000 calories) in a single meal without being uncomfortably full, but if you haven’t eaten in 20–24 hours and had some intense workouts in there, you metabolize it pretty fast and go right on about your day.