The only way to estimate this is to estimate what your heart rate is likely to be in those intervals and rests. Do you have data from comparable runs from which you can estimate a “typical” heart rate for typical interval / rest patterns?
You also need to know HR max for running, LTHR for running and resting HR.
If so, then you can use the formula that jpowers provided. To lay it out [assuming 45 minute workout, with 5 minutes warm up and 6 minutes cool down]:
1 In column A enter HR rest [A1], LTHR [A2] and HR rest [A3].
2 In column B, enter the estimate HR for each second of the run you intend to do [ie, 60 * 45 numbers].
3 in Column C, calculate HRR from the formula of jpowers: = (HR - HR rest) / (HR max - HR rest) [6045 numbers].
4 In column D, calculate HRR0.64exp[kHRR], with k = 1.92 for men, k = 1.67 for women [6045 numbers].
5 Calculate the sum of those 6045 numbers. This is TRIMP.
6 In column E, cell E1, calculate LTHRR = (LTHR - HR rest) / (HR max - HR rest).
7 Calculate E2 = LTHRR0.64exp[kLTHRR], with k = 1.92 for men, k = 1.67 for women
8 Calculate E3 = TRIMP of one hour at LTHR = 3600E2.
9 Estimate HRSS = TRIMP / E3.
Your actual HR history in the workout will be different from this calculation, of course.