A day without a loop – trying to quantify the difference between Sugar Surfing and looping #WeAreNotWaiting

I’ve often mentioned that one of the biggest benefits of using a loop (of any sort) is that you get time back. I’ve also estimated as to how much time that might be. I thought it would be worthwhile to try and properly quantify this by reverting to Sugar Surfing and seeing what the upshot was. It would also allow me to review what’s really involved in day to day management when trying to maintain half decent levels and time in range.

How do you approach such a task?

Firstly, you leave your loop at home. So, consciously leaving it in the kitchen I left the house for work at 8.45am, knowing that I’d not have the cover of the loop for the day, and making the decision to record each check that I did and decision I would make throughout the day.

I hoped the outcome would be okay and that we’d end up with some decent data. So then….

What happened?

I checked my CGM frequently. Very frequently as it turned out. 35 times in total between 8.45am and 11pm. That means that throughout the day, I made 35 decisions relating to trying to keep my glucose levels in check. Some of those were as simple as “Do nothing” and took 10 seconds. Others were more involved and required me to consider what insulin I’d dosed, the trajectory of the glucose plot and what I’d need to do to keep myself in range. I estimated that these took me around 30-45 seconds depending on the situation, and in cases where a reasonable bolus was required, my attention was held waiting for the buzz of bolus completion. On the older Medtronic pumps, this can be 5 minutes later.

This is the timetable for the day. The totals amount to:

  • 18 events that resulted in doing nothing (approximately 10 seconds a go)
  • 13 events that resulted in insulin adjustments (decision time 30 seconds each plus action 30 seconds)
  • 2 events that resulted in carb consumption (decision time 30 seconds each, plus action 30 seconds)
  • 2 other events

0845 – check – do nothing

0915 – check – 0.5u as drinking coffee

0926 – check – 0.5u climb rate still high

0940 – check – do nothing

0952 – check – do nothing

1006 – check as having coffee

1025 – check – do nothing

1038 – calibrate CGM

1050 – check – dose 1u

1126 – check – dose 0.5u

1142 – check – do nothing

1229 – check – do nothing

1315 – Meal Pre-bolus 9u

1346 – check levels – additional meal bolus

1358 – decide to set 0 TBR for hour

1448 – check – do nothing

1508 – check – do nothing

1510 – change mind – reconsider food eaten plus BG trajectory and IOB – Square wave bolus 6u/3hrs

1524 – check – do nothing

1527 – change mind (again) – administer 3u bolus

1535 – check – do nothing

1601 – check – do nothing

1633 – check – do nothing

1655 – check – do nothing

1730 – check, do nothing after pint as drop remediate

1800 – check – do nothing

1822 – check – eat 12g carbs as heading wrong direction

1900 – check before eating. Do 8u in expectation of meal

1919 – additional bolus

2010 – check do nothing

2045 – check do nothing

2120 – check give 3u insulin for food

2226 – check & dose more

2313 – check do nothing. APS reconnected.

What does this look like in terms of overall time consumed?

Based on the breakdown at the start of this section, I estimate that it’s around 18.5 mins of doing something.

That’s 18.5 mins between 8.45am and 11.13pm. 868 minutes. 2.1% of the time in that period doing something related to diabetes.

Taking the initial meal assessments out plus the calibration of the CGM, that’s still 16 minutes out. 1.8% of the period.

That provided a distribution that looks like this:

It highlights that I probably didn’t pay enough attention in the postprandial periods, as there are more high readings than I’d like to see. It suggests that my 35 checks weren’t quite enough to pick up the increases and deal with them.

So let’s extrapolate that out. When Sugar Surfing, I spent 1.8% of my time thinking about or doing something related to Diabetes. That’s 6.7 full days a year. And that’s on a normal work day when there’s nothing unusual going on. That’s also not doing it well enough to avoid postprandial higher readings. In other words, I probably should have glanced more frequently than the average 2.5 times per hour.

When I first started to use a loop, I estimated that I would recover 12 waking days a year when compared to Sugar Surfing. Based on this analysis, that works out at around 9.9 (assuming a 16 hour waking day).

What this also highlights is just how intensive an approach to therapy Sugar Surfing is, and why not everyone wants to embark on it.

And therein lies the beauty of using a closed loop system. I’ve said it before and I’ll say it again now. You get time back. But what I haven’t mentioned in this article yet is what it also gives you is reassurance. The mention of postprandial higher readings? If you’re looping, you know the loop is predicting them and doing something about it before you get there, and similarly for when you’re heading low. You also know that if you’re not paying attention, well, it is! That’s where the real benefits lie.

It’s not just knowing that you’ll recover nearly a day a month, it’s also knowing that, well, it’s got your back. And that’s priceless.


  1. > It suggests that my 35 checks weren’t quite enough to pick up the increases and deal with them.

    I’m not sure how you can draw that conclusion after a single day?

    If you switched to Sugar Surfing after having using a loop for a long time, its natural that you would be a bit rusty and unable to maintain tight control. All you’ve managed to document here is that it took you a lot of work to do something you haven’t done for a while. I don’t say this to devalue loop, merely to point out that you’re not really comparing what you say you are.

    If you really want to compare and be honest, switch back to Sugar Surfing for as long as you’ve been looping and then compare. Given how little practice you have likely had over the last months with this technique, I’d say you had a fantastic result.

    • Hi George, whether I was able to maintain the level of management I wanted wasn’t the point. Yes, I’d agree that I haven’t done it for a while, however to maintain the standards I’d want I’d need to glance and act more regularly.

      That’s where the point of this article lies. Sugar Surfing is a great technique but it requires a fair amount of effort. Having a closed loop reduces that effort significantly and allows a little more freedom not to remember to do things when you’re otherwise engaged.

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