[Sunbathing] I tried 'visualizing light' with my Apple Watch! #34

— The real reputation and use cases for the Time in Daylight feature

In previous articles, I've discussed how light is important for sleep and our internal body clocks.
👉 Related articles:

• 'Visualizing' the light you've been exposed to

• Writing about the importance of light precisely because it's a time when we want to avoid it

• Getting in sync just by soaking up light—The science of morning natural light and 'body rhythms'

• Through what channels does the light we are exposed to have an effect?

• Sunlight was visible, yet I didn't see it

But in reality, knowing 'how much light am I actually getting?' is surprisingly difficult.

So, this time, I'll be covering the Apple Watch's 'Time in Daylight' feature.

1. An era where you can 'measure' light

The 'Time in Daylight' feature, included on Apple Watch Series 6 and later (compatible with watchOS 10), uses an ambient light sensor to automatically record the time spent in daylight. In the iPhone Health app, you can check your daily, weekly, and monthly averages, so you can see at a glance, 'How much time did I spend outside today?'

Apple itself places this feature in the 'Mental Wellbeing' category,

• mood improvement

• maintaining internal body clock rhythms

• preventing myopia in children

and other research as the background for its implementation.

2. What you can measure with Apple Watch

• Automatically estimates time spent outdoors

• Records daily, weekly, and monthly averages

In other words, it doesn't measure light strictly in lux units, but is a tool to roughly visualize 'how much time you spent outside'.

3. User feedback: Mixed reviews

Upon investigation, reactions were largely divided into two types.

🌞 Positive group (Gain-oriented)

• 'I set a goal of 30 minutes of sunbathing every day and use this feature to discipline myself'

• 'It's fun to see 'sun-filled days' appear on the graph during trips'

• 'It's useful for checking sleep and mood'

👉 For those who use it to optimize their health and lifestyle, it's a 'visualization tool for rewards'.

🌥 Negative group (Pain-oriented)

• 'In winter, it's covered by long sleeves and doesn't count'

• 'I was outside for 4 hours, but only 30 minutes were recorded'

• 'There are no notifications, so I don't notice when I'm lacking'

• 'I'm concerned about battery consumption'

👉 Especially among users in winter or high-latitude regions, there is a lot of dissatisfaction that 'it's not useful when needed'.

4. Tips for effective use

• Be conscious of outdoor time in the morning → Effective for improving sleep rhythms

• Visualize days with insufficient light roughly → Motivation for habit formation

• Record trips and activities → Can be used enjoyably as a life log

➡ It is recommended to use it as a guide for reflecting on your actions rather than for 'precise light measurement'.

5. For those who want to try it out

If you already have an Apple Watch, you can use it immediately by updating watchOS. For those who don't have one yet, check here👇

• Apple Watch SE (2nd generation)(Recommended for those prioritizing cost-performance)

• Apple Watch Series 10(For those who want the latest features)

• Apple Watch Ultra 2(Perfect for enthusiasts and outdoor types)

(*Amazon link: Reference price at the time of writing)

Summary

'Time in Daylight' is:

• Useful for building a habit of getting sunlight

• Can be combined with sleep and mood management

• However, there are challenges in winter and regarding accuracy

Light is an 'invisible nutrient'.
By visualizing your 'intake' with an Apple Watch, your daily life might just get a little more balanced.

👉 In the next article, I will introduce the 'research results actually verified by Apple'.