low carb start up and exercise

lenkearney

I try to work out three to four times a week- usually 2 weight training and 2 cardio (5 mile fast walk, 25 mi bike) and get very hungry after a workout. When you start low card- I understand there is a 2 week adjustment period while your body switches from carbs to fat burning.

What are the thoughts on exercise during that two week time frame? do it, dont do it? Limit weight training? Appreciate all thoughts..

Len

wabmester

There's no harm in trying, but you're likely to feel quickly fatigued, especially if you try higher intensity.

By going low-carb, you're depleting glycogen. That means instant bonking at higher intensities.

Replenishing electrolytes (esp sodium) is VERY important when you're exercising low carb. If you feel light headed, fatigued, or have a headache, it will most likely mean you're low on sodium.

mwyvr

Is there evidence that replenishing electrolytes is even necessary, for most people, for most non peak exercise intensities, whether the diet is low carb or not? I keep running into research that suggests that for most people, most athletes, electrolyte replenishment is unnecessary.

Regarding fuel for your activities, there's no doubt that at higher intensities glycogen reserves in muscles will be called upon; if eating very low carbs these could have insufficient energy stores to meet the need.

However a 5 mile fast walk ought not meet that condition (high intensity), but it might meet that condition if your fitness level isn't up to the challenge at present. That's ok, it will be soon enough.

It might be simply the case that your cardio vascular and muscular system - basic physiology - is still catching up to increased demands being put on it. As your fitness level improves (catches up) you'll feel correspondingly better after work outs. Be sure to give yourself rest and recovering time.

Walking and recreational riding ought to be powered fairly easily by fat stores; even distance running provided the pace is well within aerobic capacity, should be powered mostly by fat rather than muscle glycogen.

wabmester

mwyvr wrote: »

Is there evidence that replenishing electrolytes is even necessary, for most people, for most non peak exercise intensities, whether the diet is low carb or not? I keep running into research that suggests that for most people, most athletes, electrolyte replenishment is unnecessary.

Would love to see the research, but it seems there have been many cases of marathon runners, for example, who got very sick by drinking water without replenishing electrolytes.

It's more important for low-carbers because of natriuresis due to ketones in the urine. That water weight that everybody loses in the first couple weeks is mostly due to sodium losses (glycogen too, but not as much).

The entire "low-carb flu" thing is due to low electrolytes. Initially sodium, and then potassium if sodium isn't replenished.

Personally, I've had multiple episodes of light-headedness after a workout that was quickly fixed with sodium intake.

professionalHobbyist

All of my ride supplements have electrolytes.

You get 60 to 80 calories of sugar in 16 ounces of water and a bunch of electrolytes

Drink that in an hour while you burn 1000 calories it works out good

mwyvr

wabmester wrote: »

Would love to see the research, but it seems there have been many cases of marathon runners, for example, who got very sick by drinking water without replenishing electrolytes.

Did they get sick from drinking too much water without replenishing electrolytes, or sick from drinking too much? From what I've learned, it's from the latter, not the former.

There are documented cases of marathoners and other athletes falling victim to hyponatremia who consumed water or sports drinks as well as other athletes including a young footballer died; he consumed nothing but sports drinks (2014), and another footballer, perhaps a more extreme case, who died after consuming two gallons each of water and Gatorade.

Bringing this back to marathoners, a 2005 study published in the N.E. Journal of Medicine looked at participants and found a large percentage suffering from over-hydration post-race.

Out of 766 runners studied in the 2002 Boston Marathon:

At the finish line, the runners had a mean serum sodium concentration of 140±5 mmol per liter (range, 114 to 158). Thirteen percent (62 of 488) had hyponatremia, including 22 percent of women (37 of 166) and 8 percent of men (25 of 322). Three runners (0.6 percent) had critical hyponatremia (serum sodium concentrations, 119, 118, and 114 mmol per liter).

The conclusion - type of drink hand little bearing on outcome:

We could find no association between the composition of fluids consumed and hyponatremia. This finding probably reflects the relative hypotonicity of most commercial sports drinks, which have a typical sodium concentration of 18 mmol per liter, less than one fifth the concentration of normal saline. Although it is difficult to rule out some effect of the type of fluid consumed on the risk of hyponatremia, our findings suggest that the contribution of the type of fluid is small as compared with the volume of fluid ingested.

Your observation here:

It's more important for low-carbers because of natriuresis due to ketones in the urine. That water weight that everybody loses in the first couple weeks is mostly due to sodium losses (glycogen too, but not as much).

Ok that makes sense from an overall dietary requirement perspective but to me doesn't feel right from a what-should-I-consume-while-exercising perspective. If you are ingesting enough sodium through your diet every day, you ought to be fine on workout or race day. Your body probably isn't excreting much water + sodium when engaged in endurance or high intensity exercise.

wabmester

Interesting stuff.

Substantial weight gain appeared to be the most important predictor of hyponatremia and correlated with increased fluid intake.

I happened to weigh myself before and after my run this morning. I lost 2.7lbs in less than an hour. Sources on the web implied that I lost a lot of sodium, but this is suggesting I simply need to drink enough water to replace the lost weight?

I see more reading in my future.

Edit: this one wasn't very helpful:
http://www.ncbi.nlm.nih.gov/pubmed/26061675

This case demonstrates that while oral sodium supplementation does not necessarily prevent symptomatic EAH associated with over hydration, early recognition and field management with oral hypertonic saline in combination with fluid restriction can be effective treatment for mild EAH. There continues to be a lack of universal understanding of the underlying pathophysiology and appropriate hospital management of EAH.

So sodium without fluid is good, but we don't really understand it yet?

FWIW, after my run, I had a pickle. Perhaps the ideal sodium delivery vehicle.

mwyvr

I like olives a little more

wabmester

Read a bit last night. The only consensus is that too much water is bad, and that most electrolyte beverages aren't ideal because they have a lower sodium concentration than blood, so even they will dilute sodium levels somewhat.

You do lose sodium as you sweat, but it differs individually. Sodium replacement seems to help, but it appears to be better to deliver it without excess fluid.

Pretty good info here:
https://www.ultracycling.com/sections/articles/nutrition/hyponatremia2.php

And here:
https://www.ultracycling.com/sections/articles/nutrition/electrolytes.php

Note that there's still a lot of advice out there to "eat less salt" that doesn't appear to be clearly backed by science, so it's likely to be a confusing issue for a while still....

Foamroller

I think it depends on individual and lifestyle choices. I do IF and often fasted training. Because of this I have to supply with more electrolytes. Less cramping, less fatigue feeling. I eat as much salt as possible when breaking fast too. YMMV. Listen to body.

chaoticdreams

So not to hijack the thread, but question....

Before the 100+ temps hit here in Florida, I was riding my bike to work and then another 6 miles in the evening. It got hot, like scorching hot, so I quit about 2 months ago or less. I started LC over three weeks ago, tried to at least pick back up the cycling in the late late evenings and got so fatigued I almost passed out. So, is it possible to get that out of shape in a little over a month, was it the heat, or was it the diet? I'm sticking to 20g or less carb wise and eat a lot of sodium. I can go for a 2.5 mile power walk no issue, do kettlebell circuits, but the cycling? What gives?

wabmester

As mentioned above, it could be instant bonking. Your body burns mostly fat for low-intensity activities like walking. The higher the intensity, the more sugar you burn. If you deplete glycogen, you bonk, and your liver is pre-depleted with a low-carb diet.

Biking and running or any higher-intensity steady state exercise will draw on your liver glycogen.

Weightlifting or other short-burst efforts will draw on muscle glycogen, which doesn't get depleted as quickly with a low-carb diet, but you may find that those muscle stores don't get replenished as quickly, so you'll max out more quickly.

suprangela79

mwyvr wrote: »

Personally, I've had multiple episodes of light-headedness after a workout that was quickly fixed with sodium intake.

I believe this. I've noticed I feel a bit lightheaded at times after a good workout so I've been eating a bit of beef jerky afterwards and feeling goes away fairly quickly.

professionalHobbyist

I take a salt tablet before a 2 + hour ride...

Drink stuff called Sktatch. 360mg sodium. 40 mg potassium each pack
Tastes salty.

I may drink two packs.
It absolutely helps on 95+ days.

chaoticdreams

I'm eating a lot of sodium already, but okay, I'll up it pre-workout to see if that helps.

mwyvr

Heat has a huge impact on performance. It may simply be that, not electrolyte related.

chaoticdreams

And it has been hot - 96 most days with heat indexes up to 120 due to the heavy humidity. Even at dusk it's still in the lower 90's upper 80's.

wabmester

Not as hot here on the west coast, but I'm still doing most of my runs in the morning before the sun can bake me.

FWIW, I did go on a short bike ride yesterday for the first time this summer. There's a long slow hill that used to have me grunting and panting at the top. Not only did I not breath hard, but I took it in a higher gear than I used to.

What a difference a year makes. Less weight to carry, better fitness, and maybe a slight boost from new fat-burning mitochondria.