Ten Miles on the Bike, Ten on Foot, and a Thunderstorm in Between
← Click here to read this diary from the beginningApollo scheduled a longer BRICK today, starting with a 10 mile ride followed by a 10 mile run. I successfully completed both however logistically it did not work out the way I hoped because the original plan was for me to run to the rec center, which is about 2 miles away do the 10 miles on the stationary bike and then complete the remaining 8 miles or so before calling it a day however, when I woke up, it had just started to rain and so I drove to the rec center completed the bike drove back, changed my shirt and went out for the run. However, about 2 miles and it started to rain and the rain turned into a downpour, and then it started thundering. At which point I found a a tree and stood under it in a useless attempt to stay somewhat dry however, by that point I was already soaked and because it did not seem like the rain was going to stop. I pulled out my phone to call my wife, Carli to come pick me up, comically my clothes and hands, and the phone were also wet that I was unable to use the touchscreen despite many attempts and so had to squeeze the water out of my shirt to get it dry enough that I could finally unlock my phone and call her.
I came home and took a hot shower and decided to call it a day due to the weather however after about two hours or so I just could not get past the idea of not completing the run and so I grabbed my tennis shoes. My running shoes went upstairs and used my wife’s hairdryer to return them to a relatively dry state put on another pair of running shorts and shirt and headed out.
The run went great despite it being significantly hotter (something Apollo confirms in the following analysis) than earlier in the day and extremely humid. I took a route that I was relatively hilly compared to my usual runs and so I did spend a fair bit of time out of zone two which isn’t ideal but nonetheless, I thought it was good to do a little bit of work
At about 5 miles and I made what was effectively the final turn on the route towards home and decided to pick up the pace a little bit because I was feeling quite good and managed to complete the final 2 1/2 miles or so. I’m at a significantly faster pace than the proceeding miles. All said I could’ve easily run a half marathon today on top of the 10 miles of cycling, which seems like a pretty good sign of things to come.
🤖 Apollo (AI): the day in numbers
Three sessions, one day. The ride ended at 9:35 AM and the first run started at 10:09, so the two were 34 minutes apart rather than the five-minute transition a brick calls for. The first run’s timer kept running for 3 minutes 32 seconds after you stopped under the tree, with speed at zero and heart rate falling from 147 to 119; that dead time has been removed from the record, and the numbers below are the moving portion.
| Session | Start | Distance | Time | Pace | Avg HR | Max HR | Cap | Weather at start |
|---|---|---|---|---|---|---|---|---|
| Indoor ride | 8:57 AM | 10.0 mi | 38:49 | 15.5 mph | 133 | 151 | 140 | indoors |
| Run, part 1 | 10:09 AM | 2.08 mi | 33:59 | 16:22/mi | 140 | 153 | 145 | 69.5°F, 95% RH, feels 74.5 |
| Run, part 2 | 2:14 PM | 8.00 mi | 2:05:36 | 15:41/mi | 156 | 182 | 145 | 79.7°F, 70% RH, feels 88.3 |
The ride was 23 minutes in zone 1 and 8 in zone 2, under the cap the whole way. The morning run held 140 across both miles (138, then 143). Then the afternoon.
The afternoon run, mile by mile.
| Mile | Time | Avg HR | Max HR | Notes |
|---|---|---|---|---|
| 1 | 15:30 | 141 | 149 | the only mile near the cap |
| 2 | 15:31 | 150 | 159 | |
| 3 | 16:25 | 155 | 165 | |
| 4 | 17:00 | 155 | 170 | |
| 5 | 17:14 | 155 | 164 | |
| 6 | 16:27 | 161 | 168 | half-mile pickup at 15:30, water stop at 6.3 |
| 7 | 15:06 | 161 | 178 | the fast finish begins at 6.5 |
| 8 | 12:15 | 175 | 182 |
Time in zones for the 8 miles: 2 minutes in zone 1, 35 in zone 2, 69 in zone 3, 19 in zone 4, and 37 seconds in zone 5. Garmin’s elevation gain for the route is 77 feet against 13 to 40 feet on every other run since mid-August, so the route was two to six times hillier than usual by that measure, though 77 feet over 8 miles is still a gentle course in absolute terms.
The afternoon: the remaining 8 miles
🤖 Apollo (AI): why the heart rate sat above zone 2
Three causes, in order of size. You named heat, hills, and the deliberate fast finish. The data can put rough sizes on each.
Heat is the largest. The morning run and the first 5.5 miles of the afternoon run were at almost the same pace, 16:22 and 16:30 per mile, and the afternoon heart rate was 11 beats higher: 151 against 140. The feels-like temperature rose 14 degrees between them, from 74.5 to 88.3. The weather model built from your own runs puts the efficiency cost at about 2.2 percent per 10 degrees of feels-like temperature, which predicts most, though not all, of that gap. Same body, same day, same pace, 11 beats. That is as clean a heat comparison as training data gets. Confidence: high that heat is the main cause, moderate on the exact share.
Hills are real but small. Miles 3 to 5 carried the most climbing and were also the slowest, 16:25 to 17:14, at a steady 155. You slowed for the grades and heart rate still sat 10 above the cap. On a course with 77 feet of total gain, hills explain a few beats at most. Confidence: moderate.
The fast finish accounts for the top of the range, not the middle. Before any of it, the first 5.5 miles averaged 151 with only 15 percent of the time under 145 and 58 percent between 150 and 160. The finish is a separate thing and is treated separately below.
Put together: on that afternoon, on that route, running at the cap would have meant roughly 17:30 to 18:00 per mile for the easy portion. The plan’s cap was written for a morning start. The answer for next Sunday is not a different cap, it is a 7 or 8 AM start.
🤖 Apollo (AI): what the benchmark showed, and what it cannot
What you actually ran. The fast finish as the watch recorded it starts at 6.5 miles, after a half-mile pickup at 15:30 pace and an 8-second water stop at 6.3. From there:
| Segment | Pace | Avg HR | Max HR | Cadence |
|---|---|---|---|---|
| 6.50 to 6.75 | 12:43 | 167 | 169 | 152 |
| 6.75 to 7.00 | 12:42 | 170 | 172 | 154 |
| 7.00 to 7.25 | 12:10 | 173 | 175 | 157 |
| 7.25 to 7.50 | 12:17 | 176 | 180 | 158 |
| 7.50 to 7.75 | 12:57 | 175 | 177 | 157 |
| 7.75 to 8.00 | 12:09 | 178 | 181 | 160 |
That is 1.5 miles at an average of 12:25 per mile, heart rate 167 climbing to 178, peaking at 181 in the final strides. Cadence rose from 148 to 160. Heart rate never plateaued; it was still rising at the finish.
What this shows, directly. After a 10-mile ride, a 2-mile run, and 6.5 miles of easy running in 88-degree feels-like heat, you ran 1.5 miles at 12:25 pace with the heart rate of your half-marathon races (both prior halves averaged 174 or higher) and reported feeling good doing it. That is a durability observation and it is a legitimate one: the stamina question you set out to test was whether the legs and the will were still there late in a long day, and they were.
What it is consistent with, with caveats. Adjusting the pace for temperature with the same model, 12:25 in 88-degree feels-like heat is roughly 11:40 at 60 degrees. Your April half was run at 11:25 per mile at a similar heart rate, fresh, over 13.1 miles. A weather-adjusted pace within about 15 seconds per mile of race pace, on legs that had already covered 18.5 miles that day across two sports, is consistent with fitness at or near the April level, and possibly above it. Confidence: moderate. The confounders are real: 1.5 miles is not 13.1, heart rate at 174 for 8 minutes is not heart rate at 174 for two and a half hours, the pace was chosen freely rather than fixed, optical heart rate at this intensity has error, and the heat adjustment was fitted on easy runs and is being applied outside that range.
What it cannot show. Whether the aerobic base is bigger than it was five weeks ago. The plan’s mechanism is a lower heart rate at a fixed easy pace, and on that measure the weather-adjusted efficiency of your easy runs over the last three weeks is 0.736 against 0.728 for the three before: flat. The morning 2 miles fit that pattern exactly, 16:22 at 140, the same as Aug 25 and Sep 9. Five weeks is at the short end of the window in which aerobic adaptation becomes measurable, so flat is the expected reading, not a bad one. It does mean the fast finish is not evidence for or against the aerobic plan. Different question, different test.
What did move. Weekly run volume hit 15.1 miles, a program high. Modeled fitness reached 66.9, also a program high, up 8.8 in one week. Garmin’s half-marathon prediction dropped from 2:39:05 to 2:35:58 after Sunday, which after correcting for its known 4 percent slow bias is about 2:30. Modeled fatigue is 103.8 against fitness of 66.9, the most fatigued point of the program, which is why Monday is a full rest day.
The test that would answer the aerobic question. Thirty minutes at a fixed heart rate of 145 on a flat route in a cool morning, repeated monthly, watching pace. It is already on the list and needs a date. Wednesday, September 30, in place of that week’s easy run, is the first slot that does not collide with the Columbus ramp.