Hard to say, Richard. The crucial figures are percentages, not absolute numbers.
You need to take your resting hr, and find your max. Max hr minus resting hr gives you your heart rate range, from which you calculate your percentages.
Example: my resting is 40, max 178. Deduct min from max and my heart rate range is 138.
Today's long run came in at an average of just under 70 per cent of hr range. The 70 per cent figure is more important than the number of beats (133).
Your hrm manual will have more info on this. Or try John L Parker's Heart Monitor Training for the Compleat Idiot.
Hope this helps!