breathing function at 79% - what does that mean?

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Active member
Jun 19, 2006
West Virginia
I was unable to go yo my husband's last als clinic appt. because of work. When I'm there with him, I ask 100 questions. Last visit (4 months ago) his breathing was 92%. This time it was 79%. What does that mean? He didn't know and of course, he didn't ask the therapist. I guess it means the als is progressing to his lungs? His way of dealing with this disease is either denial and just acting on faith. But, I like to know everything - reasons, etc. Any help on explaining the 79% would be great. This result was when he was blowing into the tube in the doctor's office. Thanks! Loving wife of 33 year - Patty
Hi Patty. The 79% is his Forced Vital Capacity which is a measure of his lung capacity compared with a group the same size, age and weight as him. Going down in numbers usually means a decline in lung capacity but some points can be lost due to leakage during the test, different operators and a few other variables. This is just 1 test in a bunch that should be given to a patient with suspected breathing issues.


Al, can you tell me what some of the other breathing function tests are? My husband was in the upper 90s, then went to mid 80s. We go back to clinic at the end of Aug. & I expect his FVC will be lower yet. His cough has weakened considerably and he gets short of breath with any exertion.

I want to be able to request whatever testing would be appropriate if his FVC has dropped again. That is the only type of breathing function test they have ever done on him. Thank you!
mine was 100% last november, then checked at 67% in april.
"it's just the pollen," i said.
"no, not pollen" they told me.
in May, the pollen ran its course, but my breathing didn't feel any better.

somebody suggested that it might be the lithium, so in May i quit lithium cold-turkey. now i read that one should wean ones self off slowly--i don't know why?

now, at the end of july, my fvc is still in the 60%s, so the decline has not continued. (yea!)
i get winded if i really exert myself. i can still bike, but i need time to catch my breath we say "intense intimacy".

i'm supposed to be getting a bi-pap machine, but
two sleep studies, plus one other "insurance billing opportunity" and all i've got is yet another appointment.
they sure do have some lovely water fountains at duke though. i hope they're putting some of that money into research.
Fvc %

Hi Patty

I have been married to my husband for 35 years. So we have something beside our names in common.

My husband has a 20% FVC at his last visit. His ALS has affected his diaphram muscle that pushes the oxygen in his lungs. His oxygen level is super but the muscle is very very weak. His bipap machine really helps him. Today, he was off the machine for about 6 hours during the day. His ALS affects upper body, his legs are still strong and he can walk, thank God.

Keep in touch and let us know how your hubby is doing.


"praying everyday for a cure for all with ALS"
Just FYI, my mom was diagnosed at 37% last week.

I would think the 70s are pretty good!
His way of dealing with this disease is either denial and just acting on faith.

please don't give him a hard time about not questioning this. when they told me that i had gone from 100% to 67% they were unbelievably mater-of-fact about it--just another day at the office for them. the way guys deal with stuff is, "if they tell me what to do, i'll do it." but as far as western medicine is concerned with als, there's nothing to be done anyway.

one person at the clinic did show me a simple breathing exercise that seemed to help--it was called "stacked breathing" i think i posted previously, but i don't see it now. if you're interested, let me know.

i think the bipap machine will help--or i'm living with that expectation anyway--when they finally get me the thing! it blows forced air into the nostrils so that when your mouth is closed, the lungs expand--als weakens the muscle that pulls down on the diaphragm, expanding the lungs to draw in air. so the far corners of the lung essentially collapse and become useless.

i feel like asking people to give me mouth-to-mouth. if they don't get me a machine after this next visit, i'll go to the friggin' aquarium store, buy an air pump and some tubing and make my own machine. THEN I'LL SEND THEM A BILL!
Glad to see you still have your sense of humor Adrian.


My husband was at 67% in March, 56% in June. He wears his full face Bi-Pap during the night and he is finding that he needs to put it on during the day if he's feeling fatigued. It took him awhile to adjust to the bi-pap. He is no longer having panic attacks while wearing it. However he has one heck of a sore spot on his nose where the mask hits him. They did tell us at his last appt. that if he is considering a feeding tube, it has to be inserted before his breathing goes below 50%.


My respiratory therapist told me that lung capacity is expected to decrease at the rate of about 3% per month for PALS. At my first visit at the ALS clinic, mine was 35%. I was put on a Bi-Pap and the RT showed me some lung excercises to do. I also use a hand held device that helps build muscles. With the use of all these, my last visit to the clinic on July 16, my lung capacity was 48%, my cough ability had risen, and my inhale ability had doubled.

The RT also told me that another advantage of using the BiPap is it makes it easier to breathe and gives your lung muscles a rest. I use mine at least 8 hours a day. I would urge anyone with ALS to talk with their RT and get them to show some breathing excercises. I am proof that they will help.

My mums fvc is at 40%, we just found out, but dont know what it was previously. I had read on a different thread that when its in the early 30's this signals the end? Or when its in the 60's, its giving you about a year, is this all true? I know i shouldnt but im now making calculations of exactly how long we have with her still here? She is very positive about things that she can do, but she is also negative in saying i wont be here for christmas and getting her will done, and talking about her funeral, sometimes I really feel she is getting ready to die?
Everyone's responses were very helpful and much appreciated. It seems like so many of you have such a sense of humor and acceptance. We really don't have any other choice I guess. One can either accept it and deal with the best way possible or just sit down and give up. I have had so many people tell me that my husband has been such an inspiration to them because of his wonderful attitude in handling his als. He threw out the first pitch last year at a als fund raiser at a baseball game. He collected around $1500 for ALS walk a thon. He is proactive in helping raise money for the hope of one day finding a cure. I love this forum. It helps me get through days. Thanks to all for being there. We must stay together and keep in other in prayer. Patty
i'm supposed to be getting a bi-pap machine, but
two sleep studies, plus one other "insurance billing opportunity" and all i've got is yet another appointment.
they sure do have some lovely water fountains at duke though. i hope they're putting some of that money into research.

UPDATE: They came through for me! I went to my appt and Dr was shocked that i did not have the machine yet. he had his office call the vendor and in a couple days the vendor set me up with a machine. they were very helpful.

the bipap is great--helps a lot! its a very weird feeling to put on, but i get to sleep quickly and most nights i sleep with it all night. i'm supposed to put distilled water in the humidifier piece, but my hands are no good, so i run it dry mostly.
Do you have anyone to help you with the machine? Perhaps to wash it for you on a regular basis? The humidifier really helped me with dry mouth.

Please, please, please be careful about drinking alcohol or taking muscle relaxants when your breathing has been comprimised. These thing can make it worse by relaxing the muscles and making it harder to breathe... Personally it took me like four rum fruity drinks to figure that out! So if you are that low watch what you take.......
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