What is SRT & SSC and How Do They Impact Me?
by Barry Stokes, USA Triathlon Level II and IRONMAN Certified Triathlon Coach
A couple of months ago I wrote about the importance of knowing your Sweat Rate and included a
calculation formula. Since then I've had any number of athletes tell me they are heavy
sweaters
and need to supplement with salt
. I ask if they know their sweat rate
(amount of fluid lost through sweat per hour of exercise) and their Sweat Sodium Concentration
(SSC) and of course they have no idea. To a person, not one has done a Sweat Rate
Test (SRT) (which is free) nor have they done a Sweat Sodium Concentration
(SSC) test (which is not free). Are they heavy sweaters or do they
perceive themselves to be heavy sweaters. In the BarryS Coaching's Family of Athletes we
have sweat rates that range from 20 ounces per hour to over 80 ounces per hour!
With those A
races approaching, each of us needs to know how much we sweat per hour and the
composition of our sweat so we can create a realistic hydration strategy to address fluid loss
and/or sodium loss.
Equally important as Sweat Rates is Sweat Sodium Concentration (SSC) – or
What's in Sweat?
– how many milligrams of sodium, potassium, calcium, zinc and so on
are in our sweat. SSC is not necessarily influenced by sweat rate, size, weight, or
gender of athlete; in other words, a slight female athlete with a Sweat Rate of 25
ozper hour could have a much higher SSC and therefore be losing more
sodium per hour than a bigger more heavily muscled male athlete with a Sweat Rate of 40
ozper hour. We all shed sodium in our sweat at differing levels.
A big part of our job as a Coach is to educate. We like to deal in facts when at all possible. We
can help in the athlete education process by arming our athletes with facts, not guess work
– remember the person I am a heavy sweater because sweat runs in my eyes
? Let's
compare that person to the coached athlete whom we know:
We tested coached athlete. Therefore, we know coached athlete loses X
ounces per hour in
Y
degrees temperature? Then we can figure out exactly how much fluid intake they need per
hour to help minimize dehydration (and the resulting negative impact on performance). Therefore,
we know our athlete losing X
ounces per hour needs to intake Z
ounces of fluid per
hour. We put together a HYDRATION PLAN (HP).
The hydration plan would be scheduled as Z divided by 6
(Z/6). Why 6? Because we want our
athletes drinking every 10 minutes of each hour, thus 6 drinks per hour, to replenish the sweat
losses on a schedule, not by guess work. We can't do much exacting work for the sweat running
in my eyes
person, can we?
Using real numbers, the HP would look like this: Athlete has a SR of 30 ounces per hour. We want the athlete to intake 25 ounces of Sports Drink (Infinit) and 5 ounces of water per hour. 30 oz/6=5 oz. In our example the athlete would drink 5 oz of sports drink at 10, 20, 40, 50, 60 min and 5 oz of water at 30 min. When drinking the water our athlete, if necessary, would supplement with sodium and/or calories (Napalm).
To remove all guess work from the customized athlete hydration plan we need to know how many
ounces of fluid the athlete intakes per suck on the straw or squeeze of the bottle so we know
how many swallows we need per hydration session
. How do we test this? Easy:
- Fill a water bottle or aero drink system.
- Set a glass measuring cup beside the bottle.
- Run around your house a couple of times (enough to get you a bit winded).
- Take a drink from the bottle or sip from the aero drink system (just as you would if on the bike) and then spit the fluids into the measuring cup.
Now the athlete knows they intake S
ounces of fluid per sip and how many sips they need
take to ingest 5 ounces.
Knowledge is power – facts remove the guesswork and build confidence!
By knowing your sweat rate, per sip volume and sweat sodium concentration (SSC) you
will be armed with facts and remove the guess work from your hydration plan and schedule –
the shift will be from how much do I need to drink per hour?
and do I need to
supplement with salt?
to I need to drink
.
Z/6
ounces of fluid per 10-minute
interval and I need to supplement with C
milligrams of sodium per hour
Know Thy Sweat Rate and Sweat Sodium Concentration!
Call Barry if you need training guidance or questions answered.
Be safe out there.