Training Effect & Recovery From 230 to 945 Much Higher Than Normal

What are the heart rate recordings like?

In addition to @philipshambrook 's suggestion of checking your HR readings, I'd also suggest looking at your HR zones and calculation method.

It also might just be that the watch needs to learn your level, give it a few weeks. Right now it might be thinking you are doing the work-outs you are doing after not doing any running for the previous months+years :).

My current Garmin profile has the zones calculated based on MHR of 170 and I am at age 50.  Not sure if changing the calc method will make much difference.

I rarely have ever reached a TE of 5.0 and days of recovery unless it was for a half marathon.

Here are two similar activities to compare.  Outdoor temp very similar.

FR230 w/ HR strap. 6.5 mile run 58 minutes, easy overall pace of 8:44, with one 0.5mile interval at 7:30

24 hrs recovery

3.5 TE - Impacting

Z5 34 minutes - 57%

Z4 18 minutes - 31%

152 bpm Avg HR
176 bpm Max HR

FR945. 7 miles run 1hr 6min, easy pace of 9:00.  Purposefully Easy.

4 days recovery

5.0 TE Aerobic - Overachieving

Z5 11 minutes 17%

Z4 50 minutes 75%

148 bpm Avg HR
157 bpm Max HR

220-age is a broad estimate that is really not much use. Ideally you need to properly determine your max heart rate by following any of the numerous procedures on the interweb. Or change to zone based on lactate threshold heart rate, but again, you'd need to properly determine your LTHR - again procedures on the interweb or you could try the test on the watch. however, not aware that too many folk have had good success using that test.

And then there is of course the notoriously unreliable optical heart rate for 'active' activities that is well documented on ALL watches with optical heart rate.

And finally, it might also simply be that the watch does need time to 'get to know you'. However, my feeling is:

1. Your heart rate zones are purely 'guessed' at the moment so getting those right will make a difference.

2. A chest strap will give more reliable readings than optical heart rate if you really need accurate measures of your training load.

Garmin uses % of maxHR to calculate VO2Max and a number of other metrics. If maxHR is wrong, then so are those other metrics. Garbage in = garbage out.

And if you reached 176 bpm during your run, then clearly your maximum is NOT 170 bpm.

If you need further evidence that your zones are wrong, then you should not be able to do 34 minutes in zone 5, or 50 minutes in zone 4, and it feel ëasy".

From the evidence presented, I'd suggest that your maximum HR is at least 180 bpm, and probably higher than that. If you change your maxHR to that, your zones will also follow, and you will get much more realistic TE and Recovery numbers.

How long have you had the watch?

It will likely need to settle in. It may even be a month as it sees what is normal.

Make sure it has gotten a lactate threshold (you can do a faster run, or the guided test) and VO2max measurement.