Heat shock proteins (HSP) are proteins that our bodies produce in response to a range of physiological challenges. It was originally thought that they were specifically produced in reaction to heat, hence the name. These days, though, it is understood that the body manufactures heat shock proteins in reaction to a range of stressors. Beyond simply responding to excess heat, they will also be produced as a reaction to load-bearing exercise, a lack of oxygen, UV light, and even, paradoxically enough, excess cold.
The functions of proteins are related to their structure. If proteins are misfolded, as a sizeable minority are, they cannot function adequately or fulfil their allocated role. Thus they simply become a burden to our cells. The fact that we can address this problem by using the body’s hormetic response is what makes heat shock proteins so intriguing for anyone interested in health and longevity.
Hormesis is the body’s way of responding to a stressor. Such stresses can come in many forms such as a toxin, heat, cold, or UV rays. A hormetic response enables the body to be better able to cope with the appropriate stressor in the future. Exercise, for example, can be thought of as a technique to elicit a hormesis response. By pushing our bodies to a point where they are uncomfortable, we make them better able to respond by becoming stronger, more athletic, or increasingly tolerant of heat and cold (1).
In simple terms, it seems that the body will produce heat shock proteins in response to almost anything that it perceives as a threat. They work by checking proteins to see if they are folding correctly. Newly produced proteins will be checked and corrected if they are misfolded. They will also create better conditions for misfolded proteins to function normally. Essentially, misfolded proteins are captured by the heat shock proteins and refolded. This will turn proteins that would be essentially a burden on the cell into proteins that are able to perform useful cellular functions.
What can we do about triggering Heat Shock Proteins
Fortunately, there is a range of ways that we can encourage our bodies to promote the use of these very beneficial proteins. Unfortunately, because these interventions are primarily hormetic in nature, each one of them will call for us to experience an amount of discomfort. Happily, the amount necessary to elicit the desired hormetic response is not excessive. Many of these activities can actually be experienced as pleasurable or, at the very least, tolerable.
Exposure to Excessive Heat
The first and most obvious way that heat shock proteins are produced is in response to heat. Taking regular saunas at sufficiently high temperatures and duration will produce heat shock proteins. In the recent Finnish study, the greatest benificiaries were those who took four to seven saunas a week for at least eleven minutes a time. Most took longer. The average temperature of these saunas was around 179 degrees Fahrenheit (82 Celsius).
Other forms of heat exposure may include hot springs, steam baths like the Turkish hammam, or even a sufficiently hot bath. Obviously, be somewhat careful with the latter.
Exposure to Excessive Cold
Strangely enough, exposure to a sufficiently cold environment, especially if it is relatively sudden, will also produce heat shock proteins. My own preference in this regard is a cold shower. This is both simple and readily available. I have also tried sitting outside in a pair of shorts when the temperature is below 0 degrees celsius. This works quite well as well and is surprisingly easy to get used to. I usually limit such exposure to 15 minutes at a time, using it as a chance to catch up on a podcast or to read.
Another way is ice baths. These are currently very much in fashion due to the work of Wim Hof. I have yet to experience ice baths, though I have swum in cold rivers. A neighbour who has experienced ice baths tells me that they are no harder than cold showers. A fourth way would be swimming in sufficiently cold water. Again, because of the nature of such an environment, sensible precautions need to be taken.
Exposure to Physical Load Bearing Exercise
Load-bearing exercise can trigger heat shock proteins in a number of ways. The increase in mechanical stress because of the weights involved is perhaps the most obvious. Beyond this though, it is thought that exercise-induced decreases in blood flow and decreases in glucose may also play a role in triggering the release of heat shock proteins (2).
HSPs help to transport proteins, a useful function if you are trying to build muscle. They also repair cellular damage in muscles and, if necessary, replace proteins where needed. This all helps to attract the amino acids needed to be converted into muscle.
One of the key functions as far as heat shock proteins are concerned is chaperoning. This term is used to describe their role in regulating and assembling proteins as they are formed into their 3-dimensional structure. Up to a third of our eukaryotic cells are misfolded. This being the case, it is clear that having fully functional and working heat shock proteins is vital to our health and longevity (3).
High-Intensity Interval Training
Similarly, sprinting has also been shown to trigger heat shock proteins. This is yet another reason to consider adding high-intensity interval training to your exercise routine. Of late, the definition of HIIT has become a little loose, hence people have been using the term HIRT (High-Intensity Repeat Training), referring to a more precise version which is perhaps a little closer to the original spirit of HIIT.
Human beings, especially those involved in the exercise world, have a disturbing tendency to take things to extremes. Hence we have such masochistic and self-destructive notions as ‘no pain, no gain’. Originally, HIIT stressed short but powerful efforts, interspersed with a decent amount of recovery. Over time though, this has morphed into harder and longer efforts and shorter and shorter recovery periods. HIRT is essentially an attempt to reset that balance.
HIRT sessions tend to stop well short of the extremes that some now go to with HIIT. The way to do HIRT is to exert yourself powerfully but only for a pretty short period. Efforts of only ten to fifteen seconds can be quite enough. This is then followed by a sufficiently long recovery period, say a minute or two at least. Finally, the number of repeats you actually perform is also much more limited. The idea is to be able to repeat the same standard on each repetition. If that standard is declining, then it is time to stop (4)
It is likely that both HIIT and HIRT will trigger heat shock proteins but HIRT will be less likely to damage your body in the long term. I see HIRT as far more in the spirit of the original version of HIIT than the current version has evolved into. Essentially, we want more bang for the buck. HIIT is a lot of bucks and we may get more or less the same bang from HIRT. This being the case, it would appear more logical, and safer, to follow the latter.
As someone who has practised intermittent fasting (IF) for five years now, it was very welcome when I read that following such a regime was also helpful for triggering heat shock proteins. In a sense, heat shock proteins may be better thought of as stress shock proteins, as almost any hormetic stress tends to trigger the utilisation of this process.
Fasting, as you are no doubt already aware, comes with a range of benefits from autophagy to ketosis. As ever, care should be taken not to overdo it. This is particularly the case if you are advancing in years or female. In both these instances, a gentler schedule is indicated. That said, one can still do 14 to 20-hour fasts on a regular basis with little or no fear of any negative consequences. Given the multiplicity of potential benefits, it seems clear that IF should play at least some part in your regular health regime (5).
Exposure to UV rays
Ultraviolet rays, whether A or B, will also tend to trigger our heat shock proteins. Again, this is a hormetic response on the part of the body. Such exposure will be generally healthy as long as we do not overdo it.
Much work is currently going on in the field to try to gauge exactly what would be a therapeutic dose of UV rays and which level would be too much. There is a sweet spot to be found, as is the case with most hormetic processes. We need enough to stimulate the body to protect itself, but not so much that we actually end up damaging tissue in some way (6).
Hypoxia (shortage of oxygen)
Recent studies on newborn guinea pigs indicate that heat shock proteins are triggered by hypoxia. HSPs during hypoxia may be acting as a potential neuronal autoprotective mechanism. They are attempting to prepare the brain from the negative effects of future hypoxic stress(7).
This is good news for those of us who have been practising breath-hold techniques for years. My own efforts have been relatively modest. On a good day, I can manage two lengths of a 25-metre pool underwater or 5 minutes of static apnea. Surprisingly, there is something very peaceful, almost meditative, about the process.
From personal experience, it is noticeable how one’s perception of discomfort changes over time. Efforts that were originally quite stressful are experienced as fairly normal after regularly partaking in these activities.
It should be stressed that if you choose to do dynamic apnea (swimming underwater while breath-holding) in a pool, be sure to have a partner with you or at least someone who is aware of what you are doing. I once did over five minutes of static apnea (simply relaxing underwater and holding the breath). Oddly, I felt completely fine as the minutes rolled by. I did become aware at a certain stage, however, that I was feeling almost too comfortable. When I eventually surfaced, still feeling quite comfortable, I became immediately aware that the world around me was spinning alarmingly …
Sometimes, your body does not give you the signals you would normally expect. Respect the situation if there is any potential danger.
The subject of heat shock proteins is fairly complex, hence I have avoided going into too much technical detail for fear of misleading my readers. That said, it seems clear that using various stressors to trigger these proteins can have a very beneficial effect and will increase our ability to cope with these stressors in future. Jari Laukkannen, in his 2016 study into Finnish sauna, speculated that many of the numerous benefits of such heat exposure may be down to the triggering of heat shock proteins (8). It is somewhat beyond my remit to speculate here but I will say that heat shock proteins look to be a very promising area of research in as far as they affect health and longevity. Watch this space, as the saying goes!