tpsdpm

This is in response to an answer by Feltdude:
The reason that the foot becomes anesthetic is because sensory innervation has been stopped. When we go to the Dentist he/she gives you "Novocaine", and tooth, and gum are numb. You have given the patient a nerve block. This is the same occurrence that we see when the foot goes numb. You are vaguely correct in your ascertation that it is vascular, but it is the microvasculature to the nerves that creates the problem. This correlates to your suggestion regarding smoking, by way of Nicotine which creates microcirculatory impairment, thus loss of neurological function. It's the Nerve's that are essentially not working, nor sending signals to the brain.

My description of a foot which has been without blood supply for 1 hour, having totally black digits was a slight dramatization, but the toes would have been a "deep purple to black, with gangrenous changes". That is not a dramatization, but what you would see in an ER.

Your logic is sound until you state "your feet being cold will make your feet go numb". My question to you would be ..... Well, why? Please, this is not an attempt to flame you, but have the forum understand the why's.

vrkelley

tpsdpm,
So does that mean that the seat is too low, too high, improperly aligned or what???

roadwarrior

Your feet get numb because the cleats are improperly mounted. Find a bike shop that will not only determine the proper fore/aft position, but get your foot level on the pedal. You want the foot level and it's not designed that way, so the cleat/shoe and possible shim to fill the gaps will spread the pressure over a larger area stopping the numbness...a good shop can fix that for you for about $30...

feltdude

"Your logic is sound until you state "your feet being cold will make your feet go numb". My question to you would be ..... Well, why? "

Lack of circulation. Use all the big words you want, you're not correct. But I'm just a PA, and you're presumably a Doctor since you're being so high-and-mighty, so I guess I'm wrong. We can get more in depth on this in private messages if you wish.

tpsdpm

I have to defer that question to LBS, or any members who are good with bike fitment. I am still a newbie with regard to proper fitting. Medically, if your seating position is any of the above it will create a condition where the pelvis, or other lower extremity (leg) structure is compressing a nerve. The signals again can not be sent up to the brain, causing numbness.

msparks

It's the cold. Mine will get cold if it's below 60. Today I went out for the first time and it was high 40's low 50's. But I had my neoprene booties, the stayed fine the whole time and I was out over 2 hrs.

Like said above, your legs get most of the bloodflow, some there is not much going to your feet. Your hands are closer to your heart and probably get plenty. All I had on my hands were some really thin polypropalene gloves and my hands never got cold.

Alphie

The answer is quite obvious. This condition happened with your old shoes. It happens with your new shoes. Too tight socks are to blame.

Leon

I'm currently on a bike tour in America and while I was riding South from Alaska (mid-September) it was getting pretty cold (for an Aussie who's rarely been in temperatures below freezing, especially not in the middle of the day) and I also had numb toes pretty much the whole time, but a few hours after being snug in my sleeping bag each night and the feeling would eventually return. After a week or so I noticed that my big toes were numb ALL the time and so I'd nervously check each night to make sure they weren't turning a nasty black colour or something. I met this guy on the Yellowhead Highway (he was the owner of a campground just East of Telkwa (Rainbow Park), really nice guy and really welcoming to cyclists) who also often got numb toes. His podiatrist said it was Morton's Neuroma (https://www.feetnet.com/edu/neuromas/) and made up a special insole for him with a lump that pushed into the space between the balls of the big toe and the second toe. He was also a cyclist so I just figured it may have been a similar thing. I also figured it can't be too great for your feet to have a very cold metal cleat so close to the foot for ten hours every day. The good thing was that the guy gave me a pair of his old neoprene booties, what a saint and I think of him often and send thanks on every cold and wet rainy day.
It's been two months now and I still can't feel my big toes. My cousin is a podiatrist so first thing I will do when I get home is go see her and get some free medical advice...
Cheers
LEon

dcrider

I've gone through most of this thread and there are a number of plausible explanations for an otherwise perplexing (and really annoying if not dangerous) phenomenom. I appreciate the medical/physiological explanations since they go beyond the brilliant explanations of "too cold" or "shoes too tight". After experiencing this in a number of different contexts I too believe that it is a microvascular or neurological issue. I can safely say that my shoes are not too tight. If anything I ride with them strapped too loose and this happens in my mtb shoes as well. And this happens at temperatures that I would not otherwise consider too cold- 60 or less (not to mention sub 40's).

I would like to add some more facts to the case that might further the diagnosis:
This happens 30+ minutes into a ride after I am otherwise "warmed-up",
it is much more pronounced in my right (dominant) foot than my left,
it can last an hour or more after the ride regardless of massaging, warm socks, car heater or hot shower,
if I downshift and up the cadence, consequently decreasing the per-stroke pressure on the pedal, it offers a little relief,
otherwise there really isn't much at all I can do to remedy it once it has started (including unclipping and shaking out the leg),
long mtb climbs produce the same numbness, making me think that it is a pressure issue,
I moved my cleats all the way forward today which I believe did prolong the onset but it still ultimately happened towards the end of the 2 hour ride,
I have not had a proper fitting on this bike so some small adjustments could very well make a big difference,
someone mentioned nicotine causing microvascular constrictions and while I do not smoke (I fully realize this is disgusting, so reader beware) sometimes I will actually chew before a ride so I can "drop weight", if you know what I mean. Nicotine is a laxative. God I hope I didn't just start another bike fad.

While I am now going to try riding with booties and without chewing tobacco I still believe that this is a problem more likely remedied through adjustments in bike fit - ie. seat and cleat positions. If anyone has specific recommendations on this I, and the countless other unfortunate souls who have this problem, would sincerely appreciate some insight.