DAY 17 — Cycling and Walking Fitness Tracker: A Puncture, 10,000 Steps and a 99 CPAP Score
The cycling and walking fitness tracker data from today is among the most eventful single-day records of the experiment — not by design, but by circumstance. The plan was a morning photoshoot in Cambridge followed by a gentle cycle to a café in South Cambridgeshire. What actually happened was a morning photoshoot, a 6.81 km cycle that reached 31.2 km/h at its fastest, a puncture at the destination, a 2.08 km walk back pushing the bike, and a rescue operation by the wife. Three Strava activities. Over 10,000 steps. And a CPAP score of 99 out of 100 after a 12:30am bedtime involving wine and television. The data today is full of contradictions, and all of them are worth examining.
Day 17 Data Summary
| Metric | Value | Source |
|---|---|---|
| Weight (Eufy, 15:34) | 99.65 kg | Eufy |
| Weight (Hume Pod, 15:57) | 99.5 kg ↑ | Hume Pod |
| BMI | 27.8 | Eufy |
| Body fat % | 30.2% | Eufy |
| Body fat mass | 30.00 kg | Eufy |
| Water % | 49.7% | Eufy |
| BMR | 1,723 kcal | Eufy |
| CPAP score | 99/100 | CPAP App |
| CPAP usage | 07:05 | CPAP App |
| AHI | 1.8 | CPAP App |
| Mask seal | Good | CPAP App |
| Mask-off events | 3 | CPAP App |
| Blood pressure (avg) | 113/79 / Pulse 66 | BP Monitor |
| Morning walk | 2.21 km / 2,094 steps / 29:34 | Strava |
| Cycling | 6.81 km / 25:48 / 15.9 km/h | Strava |
| Walk back with bike | 2.08 km / 2,414 steps / 20:12 | Strava |
| Total steps | 10,035 | Fitbit |
| Fitbit sleep | 7h 36m / Score 84 | Fitbit |
| Metabolic Momentum | 11 (↑) | Hume Band |
| Metabolic Capacity | 71 | Hume Band |
| Strain | 82 | Hume Band |
| Recovery | 67 | Hume Band |
CPAP: 99/100 After a 12:30am Bedtime
This is the number that deserves immediate attention. Last night involved television, wine, snacks, and a bedtime of 12:30am — a pattern that has produced some of the weakest CPAP results in this series. Day 12’s late social Saturday returned a score of 78. Day 13’s 02:45 bedtime produced 78. Last night, with a similar structure but a less extreme hour, the CPAP returned a score of 99 out of 100.
Usage: 7 hours 5 minutes. AHI: 1.8 — among the lowest of the series, equalling the 1.8 recorded on Day 8’s best therapeutic night. Mask seal: Good. Mask-off events: just 3.
What is different from those earlier poor nights? The most plausible explanation is the combination of two factors: a more moderate evening than the social weekend — wine and snacks rather than a full bottle of red and a cheeseboard — and crucially, 12:30am with no alarm commitment still allowed a near-complete sleep window. The Fitbit records 7 hours 36 minutes of sleep with a score of 84. The body had time and compliance to produce a near-perfect therapeutic session despite the late start.
The full face mask held for the full session. No mid-night swap to nasal pillows appears in today’s notes — the pressure and seal issues that troubled Nights 14 and 15 have not repeated themselves tonight. The streak continues, and the mask is settling.
Blood Pressure: All Green, Every Reading
Four readings between 09:01 and 09:10 this morning:
- 09:01 — 115 / 79 / Pulse 67 — OK / OK
- 09:03 — 113 / 80 / Pulse 66 — OK / OK
- 09:06 — 109 / 77 / Pulse 65 — OK / OK
- 09:10 — 114 / 80 / Pulse 67 — OK / OK
Daily average: 113 / 79 / Pulse 66 — all readings green.
Every single value across all four readings is in the OK range. The pulse at 65–67 bpm is the lowest morning resting heart rate recorded in the blood pressure series, continuing the downward arc from above 90 bpm in the early days of the experiment. The diastolic, which briefly reached 94 on Day 12 and 92 on Day 13, has now held below 82 on every reading since.
The Activity: Three Strava Sessions and a Puncture
Today produced three separate movement recordings across the day.
Morning walk, 9:48am: 2.21 km, 2,094 steps, 29 minutes 34 seconds. A straightforward Cambridge walk before the photoshoot, comparable to Day 14’s 2.02 km session along the river.
Cycle to Franks Farm, 1:01pm: 6.81 km, 25 minutes 48 seconds, average speed 15.9 km/h, maximum speed 31.2 km/h. For context: Day 7’s ride covered 13.29 km and Day 8’s scorcher through South Cambridgeshire ran to 29.10 km at an average of 19.5 km/h. Today’s session was the shortest cycle of the series by some distance — and it still ended with a puncture. There is a lesson in there somewhere about the relationship between ambition and tyre pressure.
Walk back with bike, 1:46pm: 2.08 km, 2,414 steps, 20 minutes 12 seconds, 32 metres of elevation. Pushing a bicycle with a flat tyre across South Cambridgeshire with no repair kit is, statistically speaking, excellent Zone 2 exercise. The wife arrived. The bike was loaded. The data does not record the conversation.
Total steps across the day reached 10,035 by mid-afternoon — a solid active day consistent with the higher-movement days of this series, which has regularly hit 13,000 steps and above on the Cambridge tour and cycling days. The Strain reading of 82 on the Hume Band is the highest of the experiment, reflecting the accumulated cardiovascular load of three physical sessions rather than the modest distances individually.
Hume Band: Metabolic Momentum at 11 and Strain at 82
Both figures are the highest of the series.
Metabolic Momentum at 11 with an upward arrow has been climbing consistently across the week: from 4 on Day 13, through 6 on Days 14 and 15, to 7 on Day 16, and now 11 today. The upward arc on the weekly chart running from Sunday through to Friday is the clearest positive trend this metric has produced in seventeen days. The Band is reading the accumulated activity of the week — the Cambridge tours, the gym session, the cycling and walking — as genuine building stimulus rather than simple fatigue.
Strain at 82 is the highest single reading of the experiment, beating the 70 recorded on Day 15’s fasted gym session. Today’s figure reflects three movement sessions across the day reaching a maximum cycling speed of 31.2 km/h. Recovery at 67 is healthy — above the midpoint, indicating the body has the reserves to handle the load being placed on it.
Weight: The TV Evening in the Numbers
Eufy at 99.65 kg, Hume Pod at 99.5 kg — both up approximately 0.6 kg from yesterday’s readings of 99.05 kg and 98.9 kg. Last night’s wine and snacks are visible in both figures. Both scales still sit below 100 kg, which is the more meaningful fact. The post-social rebound that pushed weight above 101 kg after Day 12’s bottle of red has not repeated itself here — a more moderate evening producing a proportionately moderate data response.
Body fat mass at 30.00 kg has edged back to the threshold crossed earlier this week. Tomorrow’s morning reading — taken before food, after sleep, with the evening’s food volume cleared — will be the more structurally informative number.
The Cowslips
There is a photograph from today’s ride worth mentioning even in a data-driven series. The South Cambridgeshire hedgerows in mid-April produce cowslips in numbers that justify the detour entirely, puncture included. The ride ended earlier than planned. The flowers were worth the walk.
Data captured Friday 17 April 2026. Eufy reading 17/04/2026 at 15:34. Hume Pod updated 15:57. Blood pressure taken 09:01–09:10. CPAP covers the night of 16–17 April 2026. Morning walk recorded 9:48am, Cambridge. Cycling recorded 1:01pm, South Cambridgeshire — 6.81 km. Walk back with bike recorded 1:46pm. Fitbit step count and sleep data as at 15:37. Hume Band data as at 15:37.
— Day 17 of 30
