Sprinting and other dubious ideas

A good friend sent me an article on the benefits of sprinting-intervals VS long, slow distance running.  It claims that more calories are burned by short frantic, as-if-chased-by-a-rabid-Rottweiler sprints interspersed with brief breaks of slow running or walking.  

So of course, armed with this new and unwanted knowledge, I am compelled to revisit the local track with my stopwatch.

Track-running rates only slightly above treadmill-running.  But at least it affords me a relatively lesser amount of public exposure as opposed to slogging along on the major highway that slices through my town.  Very few see me on the track.  And considering the state of my hair after a good 30 minutes of running, the less seen, the better.

So my new regimen is to run like all get-out for 30-40 seconds, then collapse into a walk for about a minute, repeating the process until I hit one mile total of sprinting.  This means 8 to 12 repeats depending on the length of the sprints.  This week I ran for half a lap, then walked the other half.  According to my GPS, I can briefly push my time under a seven-minute-mile without throwing up.  Husband helpfully suggests I push it closer to Puking Level, but I don't see HIM losing his breakfast when he exercises.  And I have no intention of losing mine.

The first time I tried this, my legs quickly turned to rubber, followed by several days of hostile thigh muscles.  Usually my thighs quietly comply with whatever I put them through and my calves freak out instead.  But this time the calves were fine.  (Maybe .... due to the recent hint of warm weather and the approach of capris-season, they're happily preoccupied with the instant-tanning cream I've started to slather on them.)

(LOVE.THIS.STUFF)

Finally, an added benefit of sprinting is that it builds speed.  That would be nice.  But at my age, let's just try to hang on to what I've got, okay?   So NO NEED to send me any more articles unless they contain uplifting/cheerful advice such as ....  one really ought to drink chocolate milk after one's run.  And particularly nothing on rock-climbing or hang-gliding, please.