Positive medicine - sauna, steam rooms and cold dips

Sweatfest

My best sauna and steam experiences have been up in Gazelle resort in western Turkey (near Lake Abant), seven different saunas from hot and hotter to salt, farmyard-acoustic (!) to the Turkish hammam.  I also used to exchange with a German lad as a boy whose family would have a weekly outing to one.  So what's the medical effect of these saunas?

Sauna and steam room
What is a sauna, what'a a steam room?
Finnish sauna: dry heat, 15-30% humidity, 80-90 centigrade.  2-3 heat-cool cycles each of 15 mins+.  The Finnish are the cultural custodians of the sauna - having one in almost every home  LINK (1997)
Turkish bath / steam room: 100% humidity at 41 centigrade.  Limited research available on these.

Cardiovascular effects of sauna: 

• Equivalent stress to the system as a brisk walk LINK (1997), p. 656 
• Saunas significantly reduce the risk of cardiovascular disease and all-cause mortality LINK (2015)
• Orthostatic hypotension possible in those on antihypertensive medication, generally acceptable in cardiovascular diseased patients unless their hypertension is poorly controlled. LINK (1997), p. 657 

Respiratory effects of sauna:

• Absenteeism reduction: in children taking a once weekly sauna in two studies, and replicated in a study with an adult group after 3 months, absenteeism caused by URTI was reduced by 50% LINK (1997).  However, one study did not replicate this LINK (1994)
• Chronic/recurrent sinus symptoms: no effect of steam inhalation LINK (2016)
• Bacteria: few micro-organisms are viable above 80 degrees so sauna air is relatively sterile and risk of inhalation of active microbes is small LINK (1997), p. 656 
• Heat: in sauna, water and heat transfer to the lung tissue remains small, and hence negligible risk of thermal-induced lung damage.  LINK (1997), p. 656 

Effects of sauna on skin: LINK (2008)

• Improved epidermal blood perfusion  (by 20-40x) during LINK (1997), p. 656 and with a preserved effect after regular saunas LINK (2008) 
• Improved water-holding capacity of skin (i.e. less dry skin) and recovery of skin pH, both of which are associated with stability of the epidermal barrier and prevention of skin disease LINK (2008)  
• Unclear effects on skin turgor

Cold water immersion 
The icy plunge pool after that delightfully relaxing hot room...

• Reduces dehydration from sweat after sauna (due to more rapid cooling) and transiently induces skin oedema, thereby smoothing those wrinkles temporarily!  LINK (1997), p.655
• Cold exposure activates deposits of brown fat - which are metabolically active.  Frequent exposure to cold increases the activity of these which encourages weight loss LINK (2012) ; LINK (2014)
• Cochrane reviews have found no consistent evidence that cold dips reduce muscle soreness LINK (2015)
• It's certainly invigorating, whether after a sauna or in a wetsuit on a cold day.  Gets easier the longer you stay in.  Mechanism likely is through plasma noradrenaline, adrenaline, cortisol and endorphins LINK (1997), p. 655

Summary
Saunas seem to be much the equivalent of exercise - positive respiratory and cardiovascular effects, and a healthy glow.  Just sociably and in the calm!  As for the cold dips, well, that's just more hardcore, isn't it?!

Brass monkeys

Caesarean section suturing skills

Caesarean section

Surgery.  It's a serious business with high stakes, taking place in a brightly lit operating theatre buzzing with the competence of the practitioners.  I'm writing at the end of my 8-week obstetrics and gynaecology attachment, and having worked through the basics of the knowledge in the books, lectures and clinics, I've now assisted the surgeons in the theatre - holding instruments, and for the first time, under the watchful eye of a surgeon (and with permission of the patient), stitching closed one of the tiny incisions.  Skills have come together from one of our teaching groups, SCRUBS where students teach each other suturing classes, and also from various bits of training from the experienced consultants.

The basics of any surgery are pretty formulaic (allowing you to automate the simple bits so you can deal with the unexpected).  So there are plenty of steps to learn.

Trying to describe the atmosphere to someone who's not been in an operating theatre is a challenge.  One way is to liken it to other activities from regular life:
- in some ways the operating theatre is like a formal meeting or dining occasion (there's a dress code, formal arrangements for who is placed where, you must not start until everyone is ready, there's etiquette about who talks to whom, no elbows/leaning on the table, and depending on status you may need to ask permission to get down from the table).
- in some ways the theatre is protocol driven like following a recipe (you have a set of instructions that need a bit of interpretation, there's cutting, there's searing with a diathermy probe, and there's plenty of cleaning up to do afterwards)
- and it's also a little like a home improvement project (if it ain't broke don't fix it, you get best results if you drill pilot holes before you screw in, nails need to be hammered in, the experienced practitioner lines things up by eye, and you have to know not to meddle too much - leave when it's good enough).

Steps of learning for any surgery

• Learn the anatomy of the body region
• Learn the steps in the procedure
• Learn the names of the instruments and sutures
• Train your muscles to learn the knots

Suturing and muscle memory needed for C-section skin 

• Hand-tying the basic surgeon's knot
• The running subcuticular suture
• The Aberdeen knot
• A summary video of the skin closure used by the docs I've seen at King's Mill 

My experience has been such that the team here are quite particular about skin suturing in caesarean section, and this placement I've not had a chance to deploy those skills learned on the skin pads.  Next surgical placements will be in the new year - ENT followed by orthopaedics - we'll see what the prospects are there. 

Positive medicine - stretching and warming up

Post-run stretching at Hackney Marshes parkrun

I've run 5-15km a week for the last 25 years (somewhere approaching 7000km) and continue to do so on the medical course.  It's a part of life now - I neither love it (apart from those times when I'm super fit) nor loathe it (aside from the repetitiousness!).  Up and down Donegal mountains on the Glover Highlander, searching new streets when growing into Maidstone or settling into Bavaria, Lancashire, Sheffield, Battersea and Derby; sweating buckets against all advice in Ghana in the midday sun (ouch!), and joining running clubs in Kent, Clapham, Nairobi, Derby and Mansfield, it's been consistent at least.  I've heard a load of received wisdom about stretching over the years, precious little of which I ever imagine has been researched by the people who have told me.  And as a medic, perhaps I should now be a little better informed...

The research consensus on stretching and warming up seems to be (1) DO warm up before exercise but (2) DO NOT stretch before exercise, but instead stretch (particularly the hips) at other times.  And - stretches, like so many things, are activity specific.  May be a surprise - so below details how stretches increase range of movement, performance, and affect injuries.  Here's the evidence...

Stretching

What is the physiological effect of stretching (i.e. what's happening in your muscles)?

Acutely:

1. Analgesia - increasing your tolerance of stretch, allowing you to tolerate a greater range of movement (ROM) than you had previously  LINK (2012) ; LINK (2006), p.5
2. Stress relaxation of muscle - reducing the passive tension in a muscle.  This tends to last < 1 hour LINK (2006), p.6
3. Elastic extension - as muscle sections (sarcomeres) slide over one another (and to a lesser extent, tendons and other connective tissues stretch) - muscle is the least stiff section so extends the most LINK (2009).  
4. Plastic deformation - short sarcomeres may be torn; connective tissue at the musculo-tendinous junction may be torn, abnormal crosslinks may be torn.  At the end of the muscle's ROM, tendinous collagen may also be torn.  May occur, can be pathological, therefore stop when it hurts. LINK (2005), p.51, 65

Chronically (adaptively):

1. Stretching stimulates protein synthesis in muscle - more sarcomeres are synthesised and added to the end of the myofibril LINK (2005), p.53
2. Ruptured collagen fibres are repaired by synthesis of further collagen which reunites the fibres, adding 'links into the chain' LINK (2005), p.55 

Effect of stretching on Range of Movement (ROM) LINK (2012) ;  LINK (2014) ;

• Static stretching increases ROM maximally if load is applied between 10 and 30 seconds LINK (2012)
• 2-4 repetitions give maximal stretch (subsequent repetitions do not increase range) LINK (2012)
• ROM increase is greatest if the muscle is contracted prior to stretch
• Foam rolling appears to have a far greater influence on ROM than stretching LINK (2014), slide 28
• Acutely, the ROM increase lasts less than an hour, whether the subject is exercising or not LINK (2009)

Effect of stretching on injuries

• Stretching does not reduce the occurrence of injury LINK (2012) ;  LINK (2014), slide 8
• Static and dynamic stretching have equivalent effects; active dynamic stretching is fine (full range), ballistic stretching (full range, bouncing intensely at the ends) increases risk of damage.
• Stability-mobility paradox: highest injury rates are in people at the top and bottom 20% of the flexibility distribution curve. LINK (2014), slide 19

Effect of stretching on power

• Pre-performance static stretching reduces power by 4-30%, LINK (2006), p.8 (this was at a duration of 120 secs+ per muscle group), lower stretching of 30s+ shows little compromise- therefore stretching before exercise is not a good idea for performance.  LINK (2009)
• Post-performance (or inter-performance) appears to elicit long term performance benefits LINK (2009)
• However, increased flexibility in general does not increase running economy, so these benefits of stretching may be activity-specific LINK (2014), slide 19

Optimal level of stretch

• Greater flexibility in the hips is adaptive for running (faster runners have this) LINK (2014)
• Less flexibility than standard in the lower leg joints (i.e. knees and ankles) is adaptive for running LINK (2014)
• However, years at sitting at desks and wearing shoes may exaggerate our inflexibility, and hence it's a probably a good idea to stretch out when you're running, particularly as you age. 

Warm-up

What is the physiological effect of a warm-up?

• temperature effects on the muscles, e.g. increased nerve conduction rate, increased anaerobic energy provision LINK (2003)
• neuromuscular effects, e.g. increased intramuscular Ca2+ LINK (2014)
• psychological effects, e.g. increased exercise enjoyment and motivation LINK (2014)

Performance effects of warm-up

• Stiffness is reduced by warmup LINK (2014), slide 21
• Reduces injuries: the maximum force of energy absorbed before failure is increased if muscle groups are warmed up before training LINK (2014)

Summary guidance on warm-ups and stretching

1. You should warm-up with low intensity exercise before high-intensity exercise
2. You should stretch muscle groups for 2-4 x 10-30s after or between exercise sessions - this helps with muscle synthesis and is likely to yield performance benefits
3. You should not seek super-flexibility; a moderate range of flexibility is optimal for most activities.  For peak performance running (if that's your only sport), flexible hips and slightly stiffer-than-average ankles is probably the best combination

Runner's World offers us an (incompletely evidenced!) guide to stretches