Summer Glow: How much daylight are Apple Heart and Movement Study participants getting and why does it matter?- Data

August 29, 2024

The data presented below provide supplemental details for the study update: Summer Glow: How much daylight are Apple Heart and Movement Study Participants getting and why does it matter?

Table 1. Characteristics of the main study populations used in analyses and the sub-cohort for the regression model on perceived stress.

Characteristic	Cohort 1	Cohort 2
Total participants	58350	16509
Age category, N (%)
18-24	2281 (4.0)	203 (1.2)
25-34	9522 (16.3)	1785 (10.8)
35-44	14797 (25.5)	3561 (21.6)
45-54	13333 (22.9)	3759 (22.8)
55-64	9541 (16.4)	3337 (20.2)
65-74	6240 (10.7)	2737 (16.6)
75+	2483 (4.2)	1127 (6.8)
Assigned sex, N (%)
Female	22488 (38.7)	5845 (35.4)
Male	35543 (61.1)	10644 (64.5)
Intersex	36 (0.1)	6 (0.0)
Missing	85 (0.1)	14 (0.0)
Race/ethnicity, N (%)
Asian	2409 (4.1)	557 (3.3)
Hispanic	5452 (9.4)	1204 (7.3)
Non-Hispanic black	2234 (3.8)	548 (3.3)
Non-Hispanic white	44787 (77.0)	13465 (81.6)
More than one	1898 (3.3)	423 92.6)
Other	1175 (2.0)	273 (1.7)
Prefer not to answer	197 (0.3)	39 (0.2)
BMI, N (%)
Underweight	467 (0.8)	159 (0.1)
Healthy weight	17274 (29.7)	5209 (31.6)
Overweight	20085 (34.5)	5907 (35.8)
Obese	19565 (33.6)	5234 (31.6)
Missing	467 (0.8)	0 (0.0)
Region, N (%)
Northeast	9517 (16.4)	2814 (17.1)
Midwest	11492 (19.8)	3276 (19.8)
South	20259 (34.8)	5582 (33.8)
West	16735 (28.8)	4807 (29.1)
Territories	118 (0.2)	27 (0.2)
Missing	31 (.05)	3 (0.0)
Marital Status, N (%)
Married	34372 9 (59.1)	10610 (64.3)
Never married	11462 (19.7)	2769 (16.8)
Divorced	5348 (9.2)	1471 (8.9)
Unmarried couple	4854 (8.4)	1118 (6.8)
Widowed	970 (1.7)	319 (1.9)
Separated	825 (1.4)	172 (1.0)
Missing	321 (0.5)	50 (0.3)
Education Level, N (%)
College and above	38154 (65.6)	11763 (71.3)
Some college	14752 (25.4)	3677 (22.2)
High School	4614 (7.9)	968 (5.8)
Less than high school	474 (0.8)	76 (0.4)
Missing	158 (0.2)	25 (0.0)
Employment Status, N (%)
Employed for pay	44729 (76.9)	12273 (74.3)
In retirement	6558 (11.3)	2769 (16.8)
In school	2203 (3.8)	406 (2.5)
Taking care of house or family	1398 (2.4)	314 (1.9)
Unable to work (i.e. disability,	1395 (2.4)	293 (1.8)
illness)	1395 (2.4)	293 (1.8)
Prefer not to answer	241 (0.4)	51 (0.3)
Unemployed	1628 (2.8)	403 (2.4)
Current Smoker, N (%)
Yes	3009 (5.2)	736 (4.5)
No	48390 (83.2)	15773 (95.5)
Missing	6753 (11.6)	0 (0.0)
Anxiety, N (%)
Yes	19131 (32.9)	4277 (25.9)
No	35222 (60.6)	11828 (71.7)
Missing	3799 (6.5)	404 (2.4)
Depression, N (%)
Yes	20425 (35.1)	4888 (29.6)
No	34168 (58.8)	11262 (68.2)
Missing	3559 (6.1)	359 (2.2)

Table 1 represents the demographics for the AHMS participants highlighted in the analyses who met the initial criteria for Summer Glow: How much daylight are Apple Heart and Movement Study Participants getting and why does it matter? Cohort 1 includes every participant in AHMS who completed the common demographics survey, had at least 1 day wearing the watch at least 8 hours during daylight (est. 5:00 am – 9:00 pm) and recorded at least 1 minute in daylight passively through Apple Watch. Cohort 2 is a subgroup of Cohort 1 that contributed data in May 2024 and filled out medical history, health behaviors, had exercise minutes data and filled out at least one PSS-4 survey between May 15^th and June 15^th, 2024. The MacArthur Scale of Subjective Social Status survey responses were used to classify subjective social status. The BMI categories were defined based on the BMI classification from the Center for Disease Control and Prevention.

Table 2. Daily average sunlight exposure by month.

Month in 2024	Total Participants, N	Daily average sunlight exposure minutes (95% confidence intervals)
January	48496	30.8 (29.0, 32.5)
February	49743	43.8 (41.1, 46.6)
March	50723	58.3 (54.4, 62.2)
April	51617	74.9 (69.8, 80.0)
May	52284	91.6 (86.3, 96.9)
June	52608	102.1 (97.1, 107.1)
July	52540	98.2 (92.5, 104.0)

Table 2 represents the daily average sunlight exposure in month’s January – July 2024 with 95% confidence intervals.

Table 3. Daily average sunlight exposure by state grouped by January, April, and July.

Residence	Total Participants, N			Daily average sunlight exposure, minutes			State capital total daylight, minutes (MID)
State	January	April	July	January	April	July	January	April	July
AK	142	146	149	21.4	68.4	95.5	435.3	870.4	1044.6
AL	765	830	847	29.9	78.4	84.5	618.0	780.5	841.2
AR	295	319	325	23.4	74.5	88.4	607.8	785.7	852.3
AZ	1129	1207	1200	43.6	78.5	76.4	613.2	783.1	846.4
CA	6698	6996	7047	46.7	86.1	102.1	589.6	795.1	871.9
CO	1425	1510	1538	32.7	71.5	104.7	583.6	798.0	878.3
CT	534	563	574	21.9	63.9	105.3	572.4	803.2	890.5
DC	229	238	249	33.7	83.1	103.1	587.8	795.6	873.8
DE	140	155	162	26.6	73.7	97.4	586.4	796.4	875.3
FL	3112	3297	3355	49.9	88.7	83.4	626.1	776.5	832.6
GA	1391	1471	1513	29.6	79.1	78.3	612.0	783.6	847.7
HI	209	217	221	88.4	104.9	116.6	660.2	759.8	796.5
IA	442	490	505	21.1	60.1	99.2	573.5	802.9	889.4
ID	249	266	271	22.2	72.5	104.9	562.0	809.0	901.9
IL	1701	1816	1873	20.7	63.4	102.3	583.4	798.0	878.7
IN	812	875	896	17.8	69.6	100.1	587.1	796.2	874.5
KS	385	423	433	20.5	67.1	87.9	591.3	794.0	870.1
KY	458	485	503	18.8	77.3	92.2	626.1	776.5	832.7
LA	399	435	430	31.9	82.3	76.9	569.3	804.8	893.9
MA	1454	1528	1550	25.0	64.7	111.4	587.4	795.8	874.2
MD	1006	1073	1095	25.4	69.3	88.8	557.6	810.7	906.8
ME	221	234	235	24.1	69.5	124.3	567.1	806.0	896.2
MI	1228	1349	1397	18.7	63.9	110.3	553.8	812.9	910.9
MN	1048	1127	1149	21.2	56.6	106.9	583.2	798.1	878.8
MO	855	901	921	19.6	71.0	89.6	589.6	794.9	871.9
MS	193	210	210	27.6	77.0	76.8	618.4	780.5	840.9
MT	147	154	157	26.3	77.4	134.6	543.4	818.2	922.5
NC	1375	1484	1523	30.6	81.5	85.5	602.9	788.1	857.4
ND	87	89	81	19.1	59.9	118.3	541.6	818.9	924.4
NE	293	313	329	21.4	67.4	95.4	577.8	800.9	884.8
NH	286	295	299	21.8	60.3	112.9	564.2	807.4	899.6
NJ	1125	1205	1221	23.5	67.3	104.6	581.0	799.1	881.3
NM	290	305	303	37.2	82.2	100.0	603.5	788.0	856.9
NV	468	481	500	33.1	73.7	78.0	586.7	796.6	875.0
NY	2329	2509	2544	24.0	62.9	109.6	567.3	805.9	896.0
OH	1551	1689	1759	16.9	70.5	103.8	582.3	798.5	879.8
OK	457	498	497	23.7	73.4	84.7	604.4	787.4	856.0
OR	914	969	974	24.2	70.0	106.6	554.1	813.0	910.6
PA	1733	1834	1869	20.3	65.6	101.1	572.3	803.4	890.7
RI	171	187	185	23.3	57.2	99.9	610.9	783.9	848.9
SC	654	696	715	35.0	88.3	88.8	557.4	811.0	907.0
SD	94	98	101	26.1	57.0	104.3	601.1	789.1	859.3
TN	840	891	910	22.2	75.2	84.8	626.8	776.2	831.9
TX	3695	3925	3973	32.2	74.1	77.5	578.0	800.8	884.4
UT	740	780	777	28.8	75.2	99.3	580.6	799.2	881.5
VA	1512	1599	1629	26.6	72.6	88.9	594.5	792.3	866.5
VT	107	111	118	23.4	65.0	122.3	557.9	810.7	906.4
WA	1761	1868	1912	23.2	69.6	108.4	540.2	819.8	925.8
WI	867	942	955	19.5	58.9	108.5	565.2	807.2	898.6
WV	170	192	197	15.8	68.6	88.6	590.6	794.3	870.9
WY	77	78	74	33.0	74.3	112.5	576.1	801.7	886.4

Table 3 represents the daily average sunlight exposure for each state (and Washington DC, territories not shown due to small N) in January, April, and July. Also shown is the average amount of daylight each state gets within the month based on the state capital’s location for reference

Table 4. Daily average sunlight exposure by age and sex.

Assigned sex	Age	Total N	Daily average sunlight exposure minutes
Female	18-24	1079	54.8
	25-34	4322	57.6
	35-44	5853	61.3
	45-54	4805	61.9
	55-64	3340	66.1
	65-74	2308	69.9
	75+	781	61.1
Male	18-24	1191	67.8
	25-34	5167	70
	35-44	8904	75.7
	45-54	8511	76.4
	55-64	6186	77.7
	65-74	3929	84.6
	75+	1655	73.1

Table 4 represents the average sunlight exposure minutes estimated per day from Jan 1^st – July 31^st, 2024, grouped by age and sex.

Table 5. Associations of stress and estimated sunlight exposure.

Daily average sunlight exposure	High Stress Outcome	P-value
40 – 60 minutes	.94 (.83 , 1.06 )	0.281
60 – 90 minutes	.85 (.76, .95)	0.0032
90 + minutes	.78 (.70, .86)	0

Table 5 represents the odds ratios of a high-stress score (defined as a PSS-4 score greater than 6) in different sunlight exposure groups for May 2024. The reference group had less than 40 minutes of daily average sunlight exposure. The model was adjusted for age, assigned sex, ethnicity, self-reported relative socioeconomic status, employment status, BMI, daily exercise minutes recorded on Apple Watch, smoking status, and medical conditions including having cardiovascular conditions, breathing disorder (i.e., sleep apnea or asthma), hypertension, diabetes, anxiety, and depression.

For the update and figures associated with this data, please read: Summer Glow: How much daylight are Apple Heart and Movement Study Participants getting and why does it matter?

Get the app. Join the Study.

Add Your Heading Text Here

Recent Study Updates

Summer Glow: How much daylight are Apple Heart and Movement Study participants getting and why does it matter?

August 29, 2024

As summer winds down, it’s a great time to reflect on the benefits of daylight exposure. This article looks at time in daylight, as estimated by Apple Watch, across Apple Heart and Movement Study participants in 2024.

From Short Walks to Long Runs: Embracing all Strides for Marathon Monday

April 12, 2024

The Brigham and Women’s Hospital research team celebrates April’s Boston Marathon by analyzing walking and running workouts recorded throughout the study to share insights on just how far our participants are moving.

Celebrating Heart Month: Updated Trends in Activity and Cardio Fitness

February 5, 2024

In recognition of Heart Month, a month-long effort to encourage focus on cardiovascular health, this article provides new insights about the relationship between activity levels and cardio fitness from participants in the Apple Heart and Movement Study across 2023.

World Diabetes Day: Glucose Response to Activity and the Menstrual Cycle

November 13, 2023

The Apple Heart and Movement Study teamed up with the Apple Women’s Health Study to evaluate the effects of physical activity and the menstrual cycle on glucose.