Dry fasting: another look

oura
hrv
dry-fasting
#1

Hi folks, I mentioned dry fasting to @KetoCancerMom a few weeks ago and told her that I’d update on my experiments. I don’t think she was that interested, but here’s the latest for anyone who might be curious, since I now have some cool data.

I’ve tried a few 24-hour dry fasts and two 35/36 hour ones. Once I go past 24 hours, they’re definitely harder than normal fasting (for me) and by the end of the fast I’m really dragging. However, there’s an amazing correlation with my HRV (heart rate variability), which I’ve been tracking since February. The nights that I’m dry fasting my HRV spikes (this is good :slight_smile: see below for more). It’s not just a bit higher than normal; it’s double my usual average and 50% than my otherwise highest numbers. It’s crazy. Something in my system seems to really love dry fasting. I’ll post a graph later if I get a chance.

A few other notes:
Once I’ve had water (+salt) again, I feel great within an hour or so

It completely shifts my perception of food and hunger. After 24 hours I couldn’t care less about food, but water seems like the most amazing creation ever

Some people do this to heal serious illness and would scoff at a 36-hour dry fast (there are some crazy stories out there - 3 days, 5 days). I might try to go longer if I had some big health issues, but by what would be my second night dry, my sleep is a mess so I haven’t been inclined to try for anything longer. (My sleep is an issue with fasting in general but is definitely worse when it’s dry fasting.)

My main goal is to try to heal an old hamstring injury and also I like pushing things and seeing what I can do. These days I’m doing a fair amount of hot yoga and don’t want to combine that with dry fasting days, but if I’m in a stretch with less yoga I might try a few weeks of dry OMAD and see how I feel.

[Edited to add: HRV is the measurement of the changes from one heartbeat to another. High HRV - more variation from one heartbeat to the next - is indicative of less stress and being in a parasympathetic state.]

Dry fasting for Yom Kippur- wish me luck!
(Cancer Fighting Ketovore :)) #2

Its not that I wasn’t interested. I just wasn’t interested in it for me, and I said that it should be done carefully. Also, it kinda fell off my radar (lots of posts on here and lots going on to keep track of in life), so I’m sorry about that. I think I had said that a dry fast should be undertaken with medical supervision, as it could possibly be dangerous.

I am glad that you are doing well.

(Alex ) #3

kind of begs the question - if you feel bad when you don’t… why continue?

#4

I should have put in some emoji in my first post - dry fasting seems a bit nuts and not being interested makes a lot of sense :slight_smile:

#5

I’m very interested in the HRV correlation. Mine tends to be low in general (30 is my average, 40 is a great night, and it dips to 20s or even teens if I eat too close to bedtime). When I dry fast it jumps to 60s and 70s. I don’t know what’s going on, but that’s really intriguing to me.

Also if there’s even a small chance it will speed up healing of a really annoying hamstring injury, I’ll happily try some dry days here or there.

(Cancer Fighting Ketovore :)) #6

How do you measure HRV?

(Bob M) #7

Here are some:

I also asked Santa for the finger tip version of this one:

Sadly, Santa forgot about me.

I can’t do dry fasting, as I have to take medication three times a day. I take them with water or coffee.

(Full Metal KETO AF) #8

Yes, I agree that it’s crazy. You are becoming dehydrated and your blood volume is dropping. This causes your resting heart rate to raise trying to compensate for the lower blood pressure, not good! You are overworking your cardiovascular system. I don’t understand how this is good in any way at all. In fact it’s very unhealthy for your body to be deprived of water. So yes, “It’s crazy”. :man_facepalming:t2:

#9

Actually my resting heart rate is staying low (my Oura ring measures it through the night) and all of my other markers -both subjective and objective- improve over my usual averages in the days following a dry day.

But thanks (genuinely) for your post. I can get carried away with experiments sometimes. I don’t think I will with dry fasts because I like staying active and any drop in energy is annoying, but I appreciate your thoughts. So far I’m doing well with a day or a day and a half dry here and there.

#10

I use an Oura ring. I’m not sure that it’s accurate in absolute numbers, but it’s important to me that it’s accurate relative to its own readings. I’ve been using it since February, and so far the HRV seems to track pretty much as one would expect: after an active day but with decent recovery time it tends to be higher, after a day of not eating well it tends to be lower, stressful weeks have a much lower average than easier weeks, etc.

#11

Also a higher HRV means more variability between the heart beats, which is universally considered a sign of reduced stress and improved cardiovascular health.

I would have thought that just the stress of a fast - let alone a dry fast - would be make my HRV drop temporarily, and your theory makes a lot of sense to me. However it doesn’t actually seem to be what’s happening, especially since my actual heart rate is staying at about 45 bpm.

(Bob M) #12

The Oura ring is well respected, at least by some Pod Casters and others I’ve heard interviewed by them.

Malcolm Kendrick said he would do a blog post about HRV, but hasn’t done it yet. His take would be interesting.

#13

Thanks, Bob! I’ll keep an eye out.

I’m wondering if maybe the outer ranges of HRV (for a particular individual) are actually not a great sign?

(Bob M) #14

If you have time for a pod cast, The KetoHacking MD interviews Jason Moore in episode 31, about HRV. He’s associated with one of the links I posted above, and I remember they discussed a lot about HRV.

#15

Thank you! I have a long walk coming up, and I just downloaded it to listen this afternoon.

#16

I listened to this and found it very interesting, but no answers to why my HRV would go up during a short dry fast. Jason even discusses HRV testing before and immediately after exercise, and it responds as you would expect, dropping due to the stress of exercise and then rebounding within a few hours (or days, depending on the intensity of the exercise). The whole discussion was confirmation that high HRV is indicative of a less-stressed/more parasympathetic state.

#17

I had yet another jump in my HRV when I was on a dry fast into last night (with heart rate staying low - for me - at 45 bpm). No improvement that I can see in my hamstring injury, but I swear I was more limber in yoga class soon after my last dry fast and I’m curious to see if I notice that this week as well. I’m aware that this is subjective, but it felt like my muscle fibers were just more pliable than usual.

Another subjective but noticeable difference: somehow my hunger/satiation makes more sense to me after a dry fast. I’ve been doing a 36 hour dry stretch in the middle of a 48 hr fast, and when I re-feed and re-hydrate I’m very hungry and then very satisfied after a large meal. Sometimes my post-fast hunger is confusing - seems bottomless but then I don’t feel great if I eat a lot - but after the dry fasts it all works nicely (lots and lots of food, but I feel wonderful after).

I’ll keep updating on this thread. What I’m really hoping for is an improvement in my old hamstring injury (not that big a deal but kind of annoying) but it looks like the short dry fasts are good for me anyway, so I’ll keep throwing one in every week or so.

#18

Checking in again. I did another 35-ish hour dry fast last, with similar observations: sleep was lousy (as it often is when I fast, though it’s usually bad on the 2nd or 3rd night rather than the first) but HRV was high - even higher than the previous times - with my heart rate on the low end of my average. I recover fairly well from the bad night of sleep, which is good because I often have to dive into a really intense work day, and my HRV is still higher than normal the following night.
Feeling good overall, and I’ll try this again in a few days, this time hoping to do everything possible to improve my sleep (dark room, no electronics before bed, etc).

(Mame) #19

this is so amazingly cool I can hardly stand it. I have been fascinated with HRV and increasing it for years!!

#20

Yes, very cool! I still don’t quite understand it, but it’s been consistent: HRVs between 70 and 120% higher than my usual average.