Body Temperature

[owly]

I've worked outdoors all my life, often in very harsh conditions, exposed to the elements for long periods of time. As a result I've become more acquainted than many folks with hypothermia and the conditions that don't quite meet that description.... Pre-hypothermic conditions where your core temp drops to the point where, though you may not actually feel excessively cold, it effects your judgment, and ability to perform basic tasks... sometimes survival tasks. An avid outdoorsman, cross country skier, mountaineer, hunter, backpacker, etc, I'm very sensitive to the development of such situations. The solution is to get indoors out of the cold, and get food into you..... preferably fast energy food.
Sailing in less than ideal conditions, doing long tricks at the wheel, particularly single handed or short handed, this is a serious concern to me. Stockmen often birth cattle and sheep in the cold months, when there is snow on the ground..... It's a healthier season than later in spring where the wet warm conditions cause many health issues, but it has it's own set of problems. Catching the newborn before it becomes chilled is critical, and the solution is what is called a "calf oven". Taking a chilled calf, and placing it in a heated box... essentially a crude sauna. The cardinal rule is get it warm and get colostrum into it and it will life.........Colostrum is the first milk, which is different from later milk, loaded with life giving energy.

We humans are not much different..... get us warm and get nutrition into us, and we bounce back fairly rapidly......... I know.... I've been there numerous times.


With that in mind, I am toying with the idea of setting up the head in a boat to function as a sauna.... Not for recreation or health, but for the safety of the crew. To restore the crew to full operational condition rapidly when they become chilled. This is a safety thing as you will know if you've ever operated under low body temp conditions. The ability to make rational decisions and process the information your senses are providing you accurately are impaired by low body temp. BOATS HAVE BEEN LOST, for this reason. Not once, not twice, but numerous times. Cold and fatigue are killers. This may seem like a silly non-issue to the Florida crowd, and those who live in a slip waiting for those perfect sailing days, but for those of us who see a sailboat as a way to see far places, it should be a concern. Toughness is great... but only goes so far.



H.W.

[Tillsbury]

Makes some sense to me. Is a sauna the best place for a seriously chilled person, though? I’d be tempted to get them out of all their wet clothes and wrapped in a warm blanket sitting in front of the heater outlet. But I’m not medically qualified to know what’s best.

[atoll]

heat stroke/hyperthermia and dehydration are far more common among sailors and equally lethal in warm climates

hypothermia is far less common among sailers unless in the water or in higher lattitudes.

[billknny]

There is no bad weather, only bad clothes.

I'd much prefer a sleeping bag to share with an appropriate warm body than a "sauna" which I suspect you would find rather impractical from an energy standpoint on a boat.

If you are really that could, an electric blanket is all you really need, or a sleeping bag and a hot water bottle for us low tech sorts... Pretty easy logistics too, the crew coming on watch boils some water, and fills a hot water bottle and stuffs it in the sleeping bag the retiring watch will use. Warm and toasty...

[capn_billl]

The electric blanket is a good one. 12v are available that draw 50 watts.

[rbk]

Bad idea. People with hypothermia should be warmed slowly and by their own body heat or with the body heat of another person. When the extremities get cold so does the blood in them; if you move it back to the heart too quickly and without warming it up it can cause cardiac arrest. Blankets and skin to skin contact only.

[scherzoja]

I concur with RBK. One must be careful of core temperature afterdrop, whereby the cool blood in the extremities is recirculated too quickly, dropping the core temp. I think the chemistry changes of this colder, somewhat stagnant blood, will add to the detrimental effects of that cool blood being recirculate too quickly. It reminds me of the Star Wars scene in which a hypothermic character is submersed in bubbling, presumably ware, water; not a good idea in retrospect.


https://www.betterhealth.vic.gov.au/...ng/hypothermia

https://www.aafp.org/afp/2004/1215/p2325.html
“core temperature afterdrop”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1862672/
See page 5 of the PDF for Treatment

https://www.princeton.edu/~oa/safety/hypocold.shtml

[Chotu]

Rbk is correct. Also, I've spent a lot of my life outdoors in harsh winter conditions and hypothermia is not much of an issue if you buy the right gear.

I could live outdoors indefinitely in my old snowboarding gear. Overall Bib type snow pants, well insulated and layerable, waterproof, windproof shell and jacket, layers, waterproof mittens that go up to my elbows, hat and waterproof hood from jacket, very warm Sorel type boots.

I've actually sailed in snowstorms in this gear with no heat on the boat. Was not fun. I had to move the boat. But I didn't get cold.

[kas_1611]

Originally Posted by rbk

Bad idea. People with hypothermia should be warmed slowly and by their own body heat or with the body heat of another person. When the extremities get cold so does the blood in them; if you move it back to the heart too quickly and without warming it up it can cause cardiac arrest. Blankets and skin to skin contact only.

Correct. Rapid surface warming kills hypothermic patients although not by cooling but by producing a massive drop in blood pressure as the blood rushes back to the extremities.
When the body is cold it reduces blood flow to the extremities preserving body heat, from the liver in particular, to maintain core & brain temperature. That's why your fingers go white and numb when they get cold and why frostnip and frost bite occur in the extremities. As the body warms up again the blood flow slowly increases to the extremities as the temperature balances.

Best thing to do with any chilled person or hypothermic one is remove all wet clothing, wrap them in a blanket then a space blanket (also helps keep the wind off them) and get them to sit in the W position (leaning against a wall, sitting on the floor with knees up and have them put their hands in the armpits (we call it the HELP position (Heat Escape Lowering Position) in offshore survival training. Don't forget the head loses 25% of all body heat so ensure they are wearing a warm, windproof hat or cover their head with the blanket.

Do not give them a hot drink straight off as this can also kill but wait until they are responding to warming and they have a good fingertip capillary response then a hot chocolate can be very welcome. No coffee or tea and definitely never alcohol.

Thermal Insulation Garments can be bought for a few quid if you get the Mylar type and take up no space in a safety locker if they are vacuum packed. They look like giant orange babygrows but they work. Space blankets are good but Space Bags are even better but failing that any blanket or duvet or sleeping bag will suffice.

[valhalla360]

If you are sailing in these kinds of conditions, I would expect the boat to have heat...just crank up the heat so the interior is relatively warm.

Add in appropriate clothing so you stay warm & dry to begin with...bathroom sauna seems kind of pointless.

[GordMay]

I agree with the naysayers, for their stated reasons. A sauna just isn’t practical (nor needed) on a cruising boat.

However, in my corner of Lake superior, I know of (at least) 5* saunas which have been built on remote crown (government) land by Canadian boaters (all within a daysail of Thunder Bay). In addition to their obvious recreational value (local boaters love them), they can also serve as emergency shelter for boaters.
* Flatland, Spar, and Thompson Islands, CPR Slip (SW side of St. Ignace Island), and Swede Island (adjacent to Loon Harbor)

According to Finnish lore: “If a sauna, liquor and tobacco don’t help, your condition is fatal.”


Thompson Island sauna & dock (circa ±1990):

[capn_billl]

Originally Posted by rbk

Bad idea. People with hypothermia should be warmed slowly and by their own body heat or with the body heat of another person. When the extremities get cold so does the blood in them; if you move it back to the heart too quickly and without warming it up it can cause cardiac arrest. Blankets and skin to skin contact only.

The objective here is periodic warming way before that point.

If you just pulled someone out of the North sea, or adrift in subzero temps, it's time to radio for a medevac.

[rbk]

Originally Posted by capn_billl

The objective here is periodic warming way before that point.

If you just pulled someone out of the North sea, or adrift in subzero temps, it's time to radio for a medevac.

Yes but unless you have proper medical equipment and personnel on board you're rolling the dice as to how far along the patient is and the effects you'll have on them. You would be very surprised at how easy it is to induce hypothermia even in the tropics.

[rbk]

Originally Posted by kas_1611

Correct. Rapid surface warming kills hypothermic patients although not by cooling but by producing a massive drop in blood pressure as the blood rushes back to the extremities.
When the body is cold it reduces blood flow to the extremities preserving body heat, from the liver in particular, to maintain core & brain temperature. That's why your fingers go white and numb when they get cold and why frostnip and frost bite occur in the extremities. As the body warms up again the blood flow slowly increases to the extremities as the temperature balances.

This has some truth but is more a complex combination of several factors for those interested, including blood pressure, heart rate, temperature, blood ph, glucose/insulin/glucagon, inflammation, blood clotting and hemoglobin levels and keeping them all in balance during rewarming.

To take off from where Kas leaves off..."When the body is cold it reduces blood flow to the extremities preserving body heat, from the liver* in particular, to maintain core & brain temperature..." the cold blood from your extremities rapidly flowing back into your core further reduces your core temperature potentially leading to organ failure. *This is important as one of your livers main functions is a producer/store of glucose/glycogen that can rapidly be introduced/removed into/from the blood stream. Without a proper functioning liver you can quickly slip into hyper/hypo-glycemia, coma and death. Even a small drop in core temperature can effect how organs function. This is also why it is recommended that you do not offer hot sugary or alcoholic drinks to hypothermic victims as it can lead to complications.

If you survive the initial shock and blood pressure loss your cold blood reduces the available platelets, as the temperature increases the effects reverse and platelet counts jumps drastically which can lead to thrombosis (clotting) and stroke.

As you continue to warm your inflammatory response wakes back up and goes into overdrive leading to possible systemic inflammation. While all this is going on your glucose, electrolyte and PH levels in your blood stream as also completely out of whack due to imbalances in blood distribution, this can lead to a variety of issue as your body under/over estimates your 02/glucose/insulin/potassium levels and oxygen requirements; In short your body can’t determine exactly what you require and where and can over or under compensate for the imbalances like producing too much or too little insulin.

In hypothermic state your tissue cannot utilize oxygen creating an imbalance in 02 delivery and demand leading to hypoxic conditions system wide or isolated due to imbalances in blood flow distribution; these hypoxic condition cause your body to burn anaerobic energy stores increasing lactic acid (stuff that causes your muscles to burn when doing intense exercise) this can cause areas or system wide ph levels to decrease resulting in acidosis; As the body rewarms activating various responses that consume more blood O2 (like inflammation, involuntary shivering) this furthers the depletion of 02 in the blood and if the breathing and 02 demand hasn’t increased you’re looking at system wide hypoxia and total organ failure within minutes.

Recommendations by Kas are spot on (HELP position etc) but i will take exception to the 25% heat loss out the head as it's closer to 10%. Space blankets would be a better option than an on board sauna IMO or good mummy bag

[rbk]

Originally Posted by GordMay

I agree with the naysayers, for their stated reasons. A sauna just isn’t practical (nor needed) on a cruising boat.

However, in my corner of Lake superior, I know of (at least) 5* saunas which have been built on remote crown (government) land by Canadian boaters (all within a daysail of Thunder Bay). In addition to their obvious recreational value (local boaters love them), they can also serve as emergency shelter for boaters.
* Flatland, Spar, and Thompson Islands, CPR Slip (SW side of St. Ignace Island), and Swede Island (adjacent to Loon Harbor)

According to Finnish lore: “If a sauna, liquor and tobacco don’t help, your condition is fatal.”


Thompson Island sauna & dock (circa ±1990):

I have one in my backyard. Nothing better than sipping a drink in a 120 degree sauna then going for a stroll in your shorts at -40 or standing under a snow laden tree and giving it a solid kick lol Been using them my whole life.