Feature request: Alert when glucose has been high (or low) for a sustained period

[jmritola]

Problem

Currently, Juggluco alerts trigger when glucose crosses a threshold — for example, going above 12.0 mmol/L. This works well for catching spikes, but it misses a different and clinically important scenario: glucose that stays elevated for a prolonged period without ever crossing the high alarm threshold.

This is especially problematic overnight. It's common to drift up to, say, 10.0–11.0 mmol/L after a late meal or due to dawn phenomenon — never hitting a 12.0 high alarm, but staying elevated for hours while you sleep. You wake up having spent the entire night above range without ever being notified. A threshold-crossing alert simply can't catch this pattern because the threshold was never crossed.

During the day you might notice this on a glance at the graph, but at night there's no opportunity to check — you're relying entirely on alerts, and the current alerts aren't designed for this situation.

Proposed feature

A duration-based alert that triggers when glucose has remained above (or below) a configurable threshold for a configurable amount of time. For example:

• Alert if glucose has been above 10.0 mmol/L for 60 minutes
• Alert if glucose has been above 9.0 mmol/L for 120 minutes
• Alert if glucose has been below 4.0 mmol/L for 30 minutes

This would complement the existing threshold-crossing alerts, not replace them. The key difference: the duration threshold can be set lower than your normal high alarm, catching those persistent moderate highs that currently go unnoticed.

Why this matters

Time-in-range is one of the most important metrics in glucose management. Endocrinologists increasingly focus not just on peaks and valleys, but on how long someone spends outside their target range. A duration-based alert would help users:

• Catch overnight drifts that sit just below the high alarm threshold for hours — the single biggest gap in current alerting
• Distinguish between brief post-meal spikes (which may not need intervention) and persistent highs (which do)
• Take earlier corrective action, for example waking up to give a small correction dose rather than discovering 6+ hours above range in the morning

Possible implementation

At its simplest, this could check whether all glucose readings within the past N minutes have been above (or below) the configured threshold. If so, fire the alert. A re-alert interval setting (e.g., remind every 30 minutes while still sustained) would also be useful.

I understand that the Juggluco broadcast API allows building custom solutions externally, but this feels like a natural fit for a built-in feature given how fundamental time-in-range is to glucose management.