The Effects of Cold Therapy on Blood Pressure
There seems to be mixed information out there about the affects of ice baths on blood pressure. Some advice is to avoid cold plunge if you have high blood pressure and other reports saying that it will actually help lower blood pressure. Can you share your findings or any data you have on this?
Morning light exposure for an exhausted father of two
Hi Professor Huber. I am so happy that you've created this platform! I have two young children (9 month old and 3 year old) and since my wife has the late-night shift with crying babies, I have the morning shift, which does not allow me the 10-20 minutes of sun exposure in the morning until after she wakes up around 8-9 am, well after I've woken up around 6 am. Questions: 1. Since Melanopsin has an optimum excitation range around 450 - 480 nm (peak at 460 nm), would I be able to facilitate circadian photoentrainment (i.e. ipRGC activation) through an exposure of 10-30 minutes to a blue light in this wavelength range? Am I missing any other photoreceptors that are involved in this process? 2. What is the minimum PPFD (umol m^ -2 s^ - 1) or lux at which I can achieve this? And what is the optimal PPFD (umol m^ -2 s^ - 1) or lux at which I can achieve this? There are A LOT of articles discussing ipRGC responses to light, but most of them seem to be in mice and I am not sure whether their neurons have the same activation threshold as humans. Also, I am having a hard time converting what seems to be the standard units for these experiments (photons cm^ -2 s^ -1) into the standard PAR units (umol m^ -2 s^ - 1) that are used to measure light intensity. To your knowledge, when photon density units are given are they in moles or # of particles? I swear I know how to do stoichiometry but for some reason I keep getting really high PPFD values if using moles, and very low PPFD values if using Avogadro's number to convert # of particles to moles -- for reference, PPFD at noon on a clear summer day is about 2000+ umol m^ -2 s^ - 1 here in Colorado. 3. Do I need to excite all ipRGC subtypes or just M1 to achieve circadian photoentrainment? Do other subtypes require different wavelengths or intensities of light? I have a scientific-grade PAR meter and plenty of quality morning time "on the can", so if I could figure out an overhead lighting situation to control my circadian photoentrainment me and my body would be very happy!
prefrontal inhibition and shooting
In the latest podcast on meditation at 1:14 you mentioned a study where the prefrontal cortex was inactivated (presumed via tDCS) and those doing shooting games were more accuracy but without distinction between enemy and friend. I am familiar with tDCS use for improved learning but this sounds a lot different. Can you provide me an URL for this study? I am involved in firearms training with both civilian and police using both plain paper and realistic subjects and neurologically training responses to shoot/no-shoot stimulation. This paper might provide some additional insight into training methods. Alan Kerby
Tal Chi-Interoceptive and/or Exteroceptive
On today's podcast, you mentioned that walking meditation is exteroceptive. Would you put Tai chi in the same category? It tries to harmonize movement with meditation, thus make me wondering if it could be elements of both. Thank you and any feedback is appreciated.