Sodium. Friend or Foe?

[mnichols]

This question is specifically about cycling, not general health. I know that small amounts are necessary for bodily function, but have read lots of contradictory stuff:

Some say add sodium as it helps retain water and aids hydration

Other's say that it draws water out of the cells and causes dehydration

Some say that excess sodium causes you to sweat because the body needs to expel it, and it must be carried in water so you dehydrate

The latter is the latest explanation as to why sweat is salty - the body is using the water to expel excess salt, and it's therefore dehydrating. As opposed to the historic view that we need to replace lost salt. It's a 180 degree change.

Which is correct?

[freeflow]

No. Sweat is salty because sweat is not pure water, it comes from intra cellular fluid which for evolutionary reasons has the same salt concentration as seawater. The principle mechanism for eliminating excess salts, not just sodium, is through the kidneys into urine.

When we cycle we lose water through increased breathing rate and by sweating. After a while it becomes necessary to drink to replace lost water. Adding salts to water to make it isotonic (the same amount as found in intracellular fluid) it is easier for the body to absorb water. It is better to use a blend of salts rather than just plain old ordinary salt.

For those who say they don't sweat when they cycle I'm afraid you do. It's just that your rate of sweating doesn't exceed the rate at which the sweat evaporates off.

[Vorpal]

When you sweat you lose electrolytes, including sodium and chloride. Water does not contain electrolytes. Electrolytes aid water absorption and muscle function. Other common elctrolytes are

•Calcium
•Magnesium
•Phosphorus
•Potassium

which you can get by eating potatoes, dairy, bananas, etc.

The problem is that most people eat too much salt, much more than we need. Then, water that we should lose must be retained to dilute the salt, and maintain the correct electrolyte balance in our bodies.

If you don't have enough, salt, your body may get rid of too much water and you can become dehydrated, so both theories are correct in a way.

In general, if you make a point of replenishing other electrolytes, you will also get enough salt.

[531colin]

....... the latest explanation as to why sweat is salty - the body is using the water to expel excess salt.......

Beware of "explanations" of bodily functions when the "explanations" come from people who are trying to sell you something.
....whether that something is a "de-toxifying cure for cellulite" or an isotonic drink or a bladder to put your isotonic drink in, or membership of some sort of fitness club.

sweat contains sodium, magnesium, calcium, phosphate, chloride, and all the boys in the band in roughly the same concentrations as they are found in blood plasma, for the simple reason that altering the concentrations of the things is a pretty neat trick....something which is done by your kidneys....https://en.wikipedia.org/wiki/Renal_physiology. sweat glands are really pretty simple structures https://en.wikipedia.org/wiki/Sweat_gland which take some fluid out of the circulating blood and dump it on the skin surface, where evaporation cools you down.

Are you going out for a nice ride on your bike? If so, then general food and drink is everything you need. The restorative properties of a cup of tea and a cheese and pickle sandwich are grossly under-rated.
If you are racing at a good club level, and/or over a few hours, things are a bit different, you need to watch your nutrition and hydration to maintain good performance.

people going for a 20 minute jog carrying isotonic drinks are examples of successful marketing.

[david7591]

I mix milk with water in an approx 1:3 combination. If on a ride likely to take over three hours I will carry some jelly babies and eat three approx every hour. Less than three hours I don't bother with food, even when ride involves lots of climbing, which living in Cumbria, many of mine do. I may also carry a light sandwich, marmalade or similar if out for above five hours. On longer rides I will make sure I eat carbo-hydrates the evening before, often baked potatoes. In the morning I will have a small to moderate portion of porridge. If cycling up to three hours I will simply have a banana and class of milk for breakfast, and not bother with the carbo loading on the eve of my ride. After a long ride I mix water, milk with whey powder protein and then eat a proper meal within an hour. No science behind any of this, just what I do, and it works for me.

I used to do lots of running. I never carried water. Not required for runs of less than 90 minutes. I would often run Sunday mornings ten miles or more without breakfast. You may need water only if extremely hot or marathon training long runs over two hours.

Addressing the original question, sodium friend or foe? If you had none, you'd die. If you had too much, you may also die. So it is neither, it's just something your body needs in the appropriate quantity for good health, along with loads of other substances.

[NATURAL ANKLING]

Hi,
Someone else who does not eat enough to fart

Never carbo loaded.........................eventually the body knows what you are doing...................and it backfires.

Lose 2 % of your weight in water and performance nose dives into the tarmac.

[david7591]

Hi,
Someone else who does not eat enough to fart

Never carbo loaded.........................eventually the body knows what you are doing...................and it backfires.

Lose 2 % of your weight in water and performance nose dives into the tarmac.

I eat carbo-hydrates on the eve of a long ride because I don't like eating a large breakfast before starting cycling or any other exercise. But that's just me. We are all different, and I would not make any recommendations based on what works for me. Similarly what works for you, may not for others. We all have to experiment and figure out what works for us as individuals.

[531colin]

Carb loading is not something i have ever felt the need to do, but as i understand it, this is how it works......
We need metabolic "fuel" to power muscle contraction. The first line "fuel" is glycogen stored in muscle, the second line fuel is glycogen stored in the liver. Those stores are soon used up (20 minutes vigorous exercise?) and after that we rely on mobilising fat reserves (as fatty acid) or absorbing more carbohydrate from the gut.
So, my question related to carb. loading is simple, and it is this.....what is the period of time you have got between ingesting the carbohydrate (when its "available" to metabolise) before its deposited as fat?
I had a quick Google, which came up with times from 20 minutes to 8 hours, from sources such as bodybuilding sites and assorted lunatics/people trying to sell you something.
Anybody got an answer from an authoritative source?
(sorry for the thread drift!)

[barrym]

Not sure of I'm answering the right question but here goes. I'm diabetic, insulin reliant. One down side is low blood glucose levels, hypos. The treatment recommended by NHS is jelly babies, followed by less refined carbs such as bread. I regularly go low, and a jelly baby will get into the blood stream in 2-3 minutes! For me any way.

[Vorpal]

Carb loading is not something i have ever felt the need to do, but as i understand it, this is how it works......
We need metabolic "fuel" to power muscle contraction. The first line "fuel" is glycogen stored in muscle, the second line fuel is glycogen stored in the liver. Those stores are soon used up (20 minutes vigorous exercise?) and after that we rely on mobilising fat reserves (as fatty acid) or absorbing more carbohydrate from the gut.
So, my question related to carb. loading is simple, and it is this.....what is the period of time you have got between ingesting the carbohydrate (when its "available" to metabolise) before its deposited as fat?
I had a quick Google, which came up with times from 20 minutes to 8 hours, from sources such as bodybuilding sites and assorted lunatics/people trying to sell you something.
Anybody got an answer from an authoritative source?
(sorry for the thread drift!)

There are many, many studies on this topic, going back to the 1960s. Your best definitive source is probably a recent nutrition or sports nutrition book that references the various studies.

But even there, I think you'll find that recommendation can vary considerably. One reason for that is that the carb loading strategy has changed with time. The 'original' cycle was a 7 day one, in which the athlete first starved his/her body of carbohydrates, and then loaded it. But they later found that the starving part of the cycle wasn't necessary as long as someone had a reasonable mixed diet.

Another reason is that some of this is just down to the authors' ideas and a opinions. In general, though carbohydrate loading can extend the duration of exercise by about 20%. It is more effective for cycling than many sports; this may be because of the steady-state nature of cycling.

There are also thought to be some performance improvements from carbohydrate loading, but I don't know how much.

Most of the recommended cycles are around 2 or 3 days, now. Though, the carbohydrate intake in the period of 8 or so hours before an event is also important. I don't think that alone will obtain much improvement over a normal diet.

You could look at Nutrition and Metabolism or Advanced Sports Nutrition or other similar books that are available on Google Books. Many of the older studies are in public domain.

[531colin]

Carbohydrates that I ingest 2 or 3 days before exercise will be laid down as fat. I have enough of that already.