dry heaves after racing

Question
I am a 37yo female, 5'1'' and 106lbs.  I started running about 19 months ago. I usually run about 3-4 times a week, (between 10-16 miles).  I try to run 1 endurance run (6 miles, )1 speed workout (on the treadmill, 1 minute intervals alternating at 5.6, 6.6 and 7.0 mph for 30 minutes) and 1 regular 3 mile run (probably about 9:30 pace).  I have done a few local races.  The last 2 races I experienced dry heaves as I crossed the finish line.  The first race this happened was my first 10k.  I finished in 56:30.  I figured I had pushed too hard at this distance and that'why I dry heaved. Most recently, I raced another 5k.  I finished in 26:27 and dry heaved again!  The weather was cool enough, I felt well hydrated and it was only a 5k! In addition, I had only finished about 35 seconds faster than previous races. I assume this dry heaving is due to lactic acid buildup or pushing past my fitness level.  My question is - how can I increase my fitness level (LT?) within my current regimen? I have young kids, work full time and can only find about 4 days a week to commit to running.  I am not entirely satisfied with my 9 minute pace and would like to improve my race times.  Is this even possible with 4 days a week?  I am certainly not a "natural" runner and it has been hard for me to even reach this level, but I do enjoy it and the local races have been a great motivator.  I would just like to shoot for some improvement over the next year (and to look a little more graceful crossing the finish line!)

Thanks!!
Kim

Answer
Hi Kim
You are right about the dry heaves.Your 6 mile endurance run and 3 miler is ok,but you need to add longer intervals and a tempo run of 15 to 20 min hard but in control.Intervals...work your way up to 10x 2min 30sec.with a 1 min recovery in between.I would also reccomend you do all your running outside which would make a big difference.If you work this schedule consistently you will see some great results Kim.Let me know how it is working.If you have any other questions just get in touch Kim.

All the very best

John