Table 2.

Heart rate estimation, amplitude and SNR values from the NeXus-10 MKII device and Samsung Galaxy Note8 for dry and underwater environments at baseline temperature (18 °C).

Volunteer	Dry Environment				Underwater Environment
	Gender & Age	NeXus Heart Rate (bpm)	Smartphone Heart Rate (bpm)	Amplitude Value (au)	SNR (dB)	NeXus Heart Rate (bpm)	Samsung Heart Rate (bpm)	Amplitude Value (au)	SNR (dB)
1	F 30	83	84	0.358	12.5	94	100	0.238	4.3
2	M 32	76	76	0.356	12.9	77	84	0.204	4.2
3	M 23	72	72	0.352	12.1	70	74	0.189	4.1
4	F 37	95	94	0.322	11.8	88	92	0.184	5.2
5	M 26	83	83	0.428	12.8	92	85	0.236	5.5
6	M 29	71	72	0.383	12.6	68	73	0.241	5.3
7	F 45	64	64	0.386	11.7	70	66	0.226	5.6
8	M 27	77	78	0.327	12.1	70	73	0.177	4.2
9	M 33	76	76	0.405	13.2	75	71	0.238	4.4
10	M 26	63	63	0.323	13.1	64	68	0.178	4.2
11	M 38	80	81	0.392	12.8	77	77	0.192	4.4
12	M 25	63	63	0.391	13.8	69	65	0.187	4.6
13	M 27	73	74	0.411	11.4	74	68	0.164	4.3
14	F 72	92	92	0.315	14.1	96	91	0.168	4.8
15	F 19	76	76	0.364	14.3	78	84	0.192	5.5
16	F 21	65	65	0.292	14.5	63	69	0.115	5.1
17	F 23	75	76	0.341	13.2	76	72	0.205	4.2
18	F 22	74	74	0.313	12.9	72	80	0.215	4.4
19	M 20	68	69	0.373	13.2	70	77	0.178	4.2
20	M 19	86	86	0.364	13.1	85	94	0.113	4.5
Mean ± STD		75.9 ± 9	75.95 ± 8.9	0.39 ± 0.14	12.8 ± 1.4	75.4 ± 9	80.2 ± 10.2	0.2 ± 0.1	4.9 ± 0.7