Static Apnea training and a new PB

I've enrolled for a freediving course, so I'm trying some of the training exercises from the manual before the course starts. In doing so, I managed to increase my static Apnea PB to 3:54 min (previous was 3:36). The process of building up to it gradually, meant it was a much more enjoyable experience and a good half hour meditation.

CO2 static apnea (dry)

Increase high CO2 tolerance

Split	Phase	Time
1	Breath-up	2:00
2	Breath hold	1:00
3	Breath-up	1:45
4	Breath hold	1:00
5	Breath-up	1:30
6	Breath hold	1:00
7	Breath-up	1:15
8	Breath hold	2:00
9	Breath-up	1:00
10	Breath hold	2:00
11	Breath-up	0:45
12	Breath hold	2:00
13	Recover	0:30
10	Breath hold	2:00
11	Breath-up	0:15
12	Breath hold	2:00

O2 static apnea (dry)

Increase low O2 tolerance.

Split	Phase	Time	Avg HR
1	Breath-up	02:05.3	75
2	Breath hold	01:45.6	82
3	Breath-up	02:02.0	75
4	Breath hold	02:08.2	74
5	Breath-up	02:02.4	74
6	Breath hold	02:17.8	74
7	Breath-up	02:05.7	77
8	Breath hold	02:47.0	76
9	Breath-up	02:07.9	75
10	Breath hold	02:48.2	75
11	Breath-up	02:02.4	79
12	Breath hold	03:53.9	73
13	Recover	02:53.6	75
Summary		31:00.0	75

Static Apnea (Breath Holding) Experiments

"How long can I hold my breath?", is the question. Here are my test results:

Attempt 1	55 sec. Got panicky and was surprised how short it was.
Attempt 2	2 min. Spend time relaxing and deep breathing before.
Attempt 3	2:30 min. Did some internet research on techniques
Attempt 4	3:36 min. No alcohol for a week, a day’s rest since excessing. It was an extremely intense and somewhat unpleasant experience. My fingers started tingling at about 3 min. By the end my fore arms where numb and aching.
Attempt 5	3:54 min. Final breath hold after completing CO2 and O2 tables http://goo.gl/tG3Yl

Room to improve? Certainly, I mean, experienced freedivers go for 5 to 8 min. It seems a bit daunting though. As far as I understand I need to do:

1. Meditate before starting and get heart rate down to at least 60 bpm before starting. In my last attempt I started at 80 bpm which is quite high, and dropped to 40 by the end of the 3:36 min.
2. Do dynamic apnea training. Swimming  drills while holding my breath. e.g. Underwater lengths, freestyle breathing every 9th stroke. 5 dolphin kick per 1 breast stroke breath.
3. Static apnea exercises. http://goo.gl/tG3Yl
4. Strengthen diaphragm to enable greater long volume.
5. Learn to pack - a technique for swallowing additional air into the lungs.
6. Go on a freediving course.

Related: About freediving