Table 3.
Sleep and Sleepiness of Faroese Fishermen in Four Vessel Groups at Sea and on Land Measures Obtained from Actigraphy
| Measures | Sea | Land | ||||||
|---|---|---|---|---|---|---|---|---|
| N | Mean | ±SD | N | Mean | ±SD | F | p - value | |
| Number of sleeps/24 hour | ||||||||
| Netting vessels | 31 | 1.3 | 0.4 | 30 | 1.2 | 0.3 | 1.62 | 0.110 |
| Longliners | 89 | 1.9 | 0.3 | 66 | 1.1 | 0.2 | 248.36 | ≤0.001 |
| Trawlers | 19 | 2.1 | 0.7 | 19 | 1.1 | 0.3 | 35.53 | ≤0.001 |
| Longliner with freezing facility | 14 | 1.6 | 0.4 | 13 | 1.1 | 0.1 | 15.87 | ≤0.001 |
| All ships | 153 | 1.8 | 0.5 | 128 | 1.1 | 0.3 | 183.46 | ≤0.001 |
| Sleep duration per day/min | ||||||||
| Netting vessels | 31 | 250.3 | 94.9 | 30 | 437.1 | 101.8 | 55.00 | ≤0.001 |
| Longliners | 89 | 278.8 | 76.3 | 66 | 409.3 | 193.2 | 33.64 | ≤0.001 |
| Trawlers | 19 | 233.4 | 80.2 | 19 | 414.9 | 87.7 | 44.28 | ≤0.001 |
| Longliner with freezing facility | 14 | 332.5 | 40.8 | 13 | 430.1 | 80.6 | 16.10 | ≤0.001 |
| All ships | 153 | 272.3 | 81.8 | 128 | 418.8 | 152.7 | 104.85 | ≤0.001 |
| Sleep duration per sleep | ||||||||
| Netting vessels | 31 | 198.9 | 63.7 | 30 | 385.6 | 72.9 | 113.57 | ≤0.001 |
| Longliners | 89 | 149.3 | 48.1 | 66 | 369.4 | 151.2 | 166.28 | ≤0.001 |
| Trawlers | 19 | 117.7 | 50.0 | 19 | 382.9 | 66.3 | 193.56 | ≤0.001 |
| Longliner with freezing facility | 14 | 220.6 | 56.2 | 13 | 388.1 | 79.6 | 40.40 | ≤0.001 |
| All ships | 153 | 161.9 | 60.4 | 128 | 377.1 | 119.2 | 381.90 | ≤0.001 |
| Time difference between minutes in bed, vs minutes asleep | ||||||||
| Netting vessels | 31 | 125.9 | 52.3 | 30 | 70.1 | 29.8 | 25.95 | ≤0.001 |
| Longliners | 89 | 157.2 | 73.8 | 66 | 94.6 | 93.2 | 22.27 | ≤0.001 |
| Trawlers | 19 | 139.5 | 71.7 | 19 | 74.0 | 34.9 | 12.84 | ≤0.001 |
| Longliner with freezing facility | 14 | 125.7 | 31.3 | 13 | 89.1 | 44.8 | 6.16 | <0.05 |
| All ships | 153 | 146.3 | 68.1 | 128 | 85.3 | 71.7 | 53.46 | ≤0.001 |
| Sleep efficiency (%) | ||||||||
| Netting vessels | 31 | 68.7 | 20.0 | 30 | 84.7 | 8.2 | 134.96 | ≤0.001 |
| Longliners | 89 | 62.8 | 23.3 | 66 | 82.6 | 10.6 | 378.97 | ≤0.001 |
| Trawlers | 19 | 67.1 | 23.8 | 19 | 84.6 | 7.9 | 79.36 | ≤0.001 |
| Longliner with freezing facility | 14 | 71.7 | 15.8 | 13 | 81.9 | 9.1 | 41.19 | ≤0.001 |
| All ships | 153 | 65.4 | 22.0 | 128 | 83.3 | 9.6 | 676.02 | ≤0.001 |
| Sleep fragmentation Index | ||||||||
| Netting vessels | 31 | 72.0 | 30.6 | 30 | 31.1 | 15.9 | 330.69 | ≤0.001 |
| Longliners | 89 | 77.4 | 34.0 | 66 | 35.2 | 18.1 | 793.95 | ≤0.001 |
| Trawlers | 19 | 72.2 | 34.9 | 19 | 29.5 | 12.9 | 214.66 | ≤0.001 |
| Longliner with freezing facility | 14 | 59.0 | 27.9 | 13 | 37.3 | 16.4 | 59.83 | ≤0.001 |
| All ships | 153 | 72.6 | 33.4 | 128 | 33.6 | 16.8 | 1355.69 | ≤0.001 |
| Number of awakenings | ||||||||
| Netting vessels | 31 | 17.3 | 10.1 | 30 | 21.4 | 10.7 | 15.23 | ≤0.001 |
| Longliners | 89 | 11.7 | 7.0 | 66 | 20.8 | 10.5 | 577.29 | ≤0.001 |
| Trawlers | 19 | 8.7 | 6.4 | 19 | 19.2 | 9.3 | 152.35 | ≤0.001 |
| Longliner with freezing facility | 14 | 16.7 | 7.7 | 13 | 22.3 | 10.4 | 43.12 | ≤0.001 |
| All ships | 153 | 13.0 | 7.7 | 128 | 20.9 | 10.4 | 682.40 | ≤0.001 |
| Wake After Sleep Onset (WASO) | ||||||||
| Netting vessels | 31 | 99.6 | 85.8 | 30 | 64.0 | 40.3 | 33.72 | ≤0.001 |
| Longliners | 89 | 77.7 | 65.5 | 66 | 71.5 | 48.3 | 4.22 | <0.05 |
| Trawlers | 19 | 51.9 | 48.5 | 19 | 65.5 | 42.0 | 7.61 | ≤0.01 |
| Longliner with freezing facility | 14 | 78.2 | 54.3 | 13 | 81.2 | 53.9 | 0.29 | 0.591 |
| All ships | 153 | 77.3 | 64.0 | 128 | 69.7 | 46.4 | 13.19 | ≤0.001 |
| Sleep Latency | ||||||||
| Netting vessels | 31 | 9.2 | 19.5 | 30 | 1.8 | 3.2 | 37.15 | ≤0.001 |
| Longliners | 89 | 8.9 | 16.9 | 66 | 1.6 | 2.5 | 105.29 | ≤0.001 |
| Trawlers | 19 | 7.6 | 12.9 | 19 | 1.7 | 2.1 | 33.72 | ≤0.001 |
| Longliner with freezing facility | 14 | 4.5 | 8.7 | 13 | 2.0 | 3.5 | 8.40 | ≤0.01 |
| All ships | 153 | 7.8 | 15.5 | 128 | 1.7 | 2.8 | 171.87 | ≤0.001 |
Notes: Efficiency - number of sleep minutes divided by the total number of minutes the subject was in bed (ie, the difference between the In-Bed and Out-Bed-time). Sleep fragmentation Index - refers to the proportion of arousals (restlessness) during sleep (Gellman & Turner, 2020). Movement index – proportion of movement during sleep average awakening length - refers to the average length, in minutes, of all awakening episodes during sleep. Wake After Sleep Onset (WASO) refers to periods of wakefulness occurring after defined sleep onset. This parameter measures wakefulness, excluding the wakefulness occurring before sleep onset. Number of awakenings refers to how many periods of awakenings are recorded after defined sleep onset.