[jvanv8]

In the past 2 weeks or so, I've been experiencing shortness of breath 4-5x per ride. It starts by feeling like I'm drounding as if I only exhaled the past 5 breaths and stuggle to get air. It lasts about 4 breaths and then returns to normal. 1-2 seconds after that, I feel a cooling sensation in my head. A few times I felt unbalanced at that point. It occurs a low HRs ~ 130-138 bpm. I do long rides, 100 miles or so at low intensity (avg HR 125-138, usually in 5:08-5:25 hours). I know it isn't bonking because it has occured early in the ride when I had plenty of sugar before departing.

I generally have a low RHR and low BP if you think it matters. I ride about 1000-1600 miles per month. My favorite color is blue but my bike is black.

 

[UrbanPrimitive]

Check with a doctor. This sounds serious.

The "cooling" sensation in your head, sometimes followed by dizziness sounds like circulation to me. When I was in high school I had dangerously low blood pressure (50 over 28) and frequently passed out when standing up from a seated position. I experienced a similar "cooling" feeling before the dizziness as my vision blanked out. Seriously, if you have decent medical insurance, it'll be worth the co-pay.

 

[AdamM]

My $0.02 is that I'd put aside whatever I'm doing and go see the doctor this afternoon.

 

[nephro]

I would stay off the bike until this has been evaluated. Could be a number of things, including paroxysmal arrhythmia or other cardiac etiology. How old are you? What medical problems do you have?

 

[Hooben]

Blood pressure - high or low can happen even with low resting heart rates
Stress - panic attacks can strike anywhere and will give you shortness of breath
Allergy - could be asthma that is limiting your breathing.
Heart - either something you were born with or something that has developed.

Bottom line is go to your doctor, in a few minutes you could have an answer.